How do I solve 4 down in Daily Telegraph Cryptic 31253?

Question

Accepted Answer

4 down reads "Mac artist at home with paint" (8 letters); the answer is RAINCOAT. It's a charade: the answer breaks into parts in clue order, each part clued by a word or short phrase. No indicators needed; watch for standard abbreviations (RA = artist, US = American, IN = at home) and short synonyms. The full step-by-step breakdown is on this page.

Mac artist at home with paint (8)

4D — Mac artist at home with paint (8) — RAINCOAT