How do I solve 22 across in Times Cryptic 29538?

Question

Accepted Answer

22 across reads "Mostly drunk portrait painter is alone" (6 letters); the answer is SOLELY. It's a deletion clue: start with a word the clue points to, then drop one or more letters. Indicators include 'endlessly' (lose the last letter), 'beheaded' (lose the first), or 'heartlessly' (lose the middle). The full step-by-step breakdown is on this page.

Mostly drunk portrait painter is alone (6)

22A — Mostly drunk portrait painter is alone (6) — SOLELY