Charles Dickens was apparently quite fond of the word countenance. In David Copperfield it appears 20 times. I have not tracked Dickens’s use of countenance in the books I've read more recently (and from which I have been selecting the words of the day), but I believe it appears even more frequently in some of them. In particular, in Our Mutual Friend, the word seems to appear on average about once per page. Though I'm sure it's not that often, it can't be much less.
Small excerpts from the text in which the word countenance appears in David Copperfield are listed below. The page numbers are approximate at this point. I'll correct them soon.
My mother had a sure foreboding at the second glance, that it was Miss Betsey. The setting sun was glowing on the strange lady, over the garden-fence, and she came walking up to the door with a fell rigidity of figure and composure of countenance that could have belonged to nobody else.
David Copperfield, p. 5 (Modern Library Classics, 2000, paperback)
Steerforth continued his protection of me, and proved a very useful friend; since nobody dared to annoy one whom he honoured with his countenance.
David Copperfield, p. 73 (Modern Library Classics, 2000, paperback)
Mr Peggotty and Ham waited for us at the old place. They received me and Peggotty in an affectionate manner, and shook hands with Mr Barkis, who, with his hat on the very back of his head, and a shame-faced leer upon his countenance, and pervading his very legs, presented but a vacant appearance, I thought.
David Copperfield, p. 113 (Modern Library Classics, 2000, paperback)
My aunt, with every sort of expression but wonder discharged from her countenance, sat on the gravel, staring at me, until I began to cry; when she got up in a great hurry, collared me, and took me into the parlour.
David Copperfield, p. 153 (Modern Library Classics, 2000, paperback)
As I was delighted with the place, my aunt and Mrs Crupp withdrew into the pantry to discuss the terms, while I remained on the sitting-room sofa, hardly daring to think it possible that I could be destined to live in such a noble residence. After a single combat of some duration they returned, and I saw, to my joy, both in Mrs Crupp's countenance and in my aunt's, that the deed was done.
David Copperfield, p. 282 (Modern Library Classics, 2000, paperback)
Traces of deep-seated anguish appeared in my countenance. That she should hope I would go, that she should think it possible I could go, was insupportable.
David Copperfield, p. 312 (Modern Library Classics, 2000, paperback)
I replied that it was. Mr Micawber continued talking as volubly as he could; but not, I thought, without showing, by some marks of concern in his countenance, that he was sensible of sounds in the next room, as of Mrs Micawber washing her hands, and hurriedly opening and shutting drawers that were uneasy in their action.
David Copperfield, p. 322 (Modern Library Classics, 2000, paperback)
Mr Omer looked at me, with a steady countenance, and shook his head.
David Copperfield, p. 345 (Modern Library Classics, 2000, paperback)
Peggotty was glad to get it for him, and he overwhelmed her with thanks, and went his way up Tottenham Court Road, carrying the flower-pot affectionately in his arms, with one of the most delighted expressions of countenance I ever saw.
David Copperfield, p. 391 (Modern Library Classics, 2000, paperback)
'To be sure there is,' said I. 'But all we can do just now, Mr Dick, is to keep a cheerful countenance, and not let my aunt see that we are thinking about it.'
David Copperfield, p. 396 (Modern Library Classics, 2000, paperback)
He appeared to be only too conscious of it himself. When he came in, he stood still; and with his head bowed, as if he felt it. This was only for a moment; for Agnes softly said to him, 'Papa! Here is Miss Trotwood - and Trotwood, whom you have not seen for a long while!' and then he approached, and constrainedly gave my aunt his hand, and shook hands more cordially with me. In the moment's pause I speak of, I saw Uriah's countenance form itself into a most ill-favoured smile. Agnes saw it too, I think, for she shrank from him.
David Copperfield, p. 409 (Modern Library Classics, 2000, paperback)
What my aunt saw, or did not see, I defy the science of physiognomy to have made out, without her own consent. I believe there never was anybody with such an imperturbable countenance when she chose. Her face might have been a dead-wall on the occasion in question, for any light it threw upon her thoughts; until she broke silence with her usual abruptness.
David Copperfield, p. 409 (Modern Library Classics, 2000, paperback)
I was going on at a great rate, with a clenched hand, and a most enthusiastic countenance; but it was quite unnecessary to proceed. I had said enough. I had done it again. Oh, she was so frightened! Oh, where was Julia Mills! Oh, take her to Julia Mills, and go away, please! So that, in short, I was quite distracted, and raved about the drawing-room.
David Copperfield, p. 429 (Modern Library Classics, 2000, paperback)
I submitted; and, with a countenance as expressive as I was able to make it of dejected and despairing constancy, came out of the room. Miss Murdstone's heavy eyebrows followed me to the door - I say her eyebrows rather than her eyes, because they were much more important in her face - and she looked so exactly as she used to look, at about that hour of the morning, in our parlour at Blunderstone, that I could have fancied I had been breaking down in my lessons again, and that the dead weight on my mind was that horrible old spelling-book, with oval woodcuts, shaped, to my youthful fancy, like the glasses out of spectacles.
David Copperfield, p. 438 (Modern Library Classics, 2000, paperback)
'Now, I'm not a-going to let myself be run down, Copperfield,' he continued, raising that part of his countenance, where his red eyebrows would have been if he had had any, with malignant triumph, 'and I shall do what I can to put a stop to this friendship. I don't approve of it. I don't mind acknowledging to you that I've got rather a grudging disposition, and want to keep off all intruders. I ain't a-going, if I know it, to run the risk of being plotted against.'
David Copperfield, p. 481 (Modern Library Classics, 2000, paperback)
Her name was Paragon. Her nature was represented to us, when we engaged her, as being feebly expressed in her name. She had a written character, as large as a proclamation; and, according to this document, could do everything of a domestic nature that ever I heard of, and a great many things that I never did hear of. She was a woman in the prime of life; of a severe countenance; and subject (particularly in the arms) to a sort of perpetual measles or fiery rash.
David Copperfield, p. 502 (Modern Library Classics, 2000, paperback)
Dora put his nose to mine, and said 'Boh!' to drive my seriousness away; but, not succeeding, ordered him into his Pagoda, and sat looking at me, with her hands folded, and a most resigned little expression of countenance.
David Copperfield, p. 551 (Modern Library Classics, 2000, paperback)
I was thinking. And had I truly disciplined my heart to this, and could I resolutely bear it, and calmly hold the place in her home which she had calmly held in mine, - when I found my eyes resting on a countenance that might have arisen out of the fire, in its association with my early remembrances.
David Copperfield, p. 660 (Modern Library Classics, 2000, paperback)
'Well, sir,' returned Mr Chillip, smiling very meekly, and shaking his head as he surveyed me, 'I have a kind of an impression that something in your countenance is familiar to me, sir; but I couldn't lay my hand upon your name, really.'
David Copperfield, p. 661 (Modern Library Classics, 2000, paperback)
Who is this bent lady, supporting herself by a stick, and showing me a countenance in which there are some traces of old pride and beauty, feebly contending with a querulous, imbecile, fretful wandering of the mind? She is in a garden; and near her stands a sharp, dark, withered woman, with a white scar on her lip.
David Copperfield, p. 696 (Modern Library Classics, 2000, paperback)