How do I solve 18 down in Express Cryptic 20260521?

Question

Accepted Answer

18 down reads "School's first head taking notice in misery" (7 letters); the answer is SADNESS. 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.

School's first head taking notice in misery (7)

18D — School's first head taking notice in misery (7) — SADNESS