Sentence:  At first, not knowing any better, I used sometimes to copy a nude on the pavement. The first I did was outside St Martin's-in-the-Fields church. A fellow in black—I suppose he was a <WSD>churchwarden</WSD> or something—came out in a tearing rage. 
Meaning of the word marked with <WSD> tags:  A lay officer of the Church of England who handles the secular affairs of the parish.