How do I solve 12 across in Express Cryptic 20260529?

Question

Accepted Answer

12 across reads "Make too much effort concerning river, right?" (9 letters); the answer is OVEREXERT. 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.

Make too much effort concerning river, right? (9)

12A — Make too much effort concerning river, right? (9) — OVEREXERT