Simplified from 鈎 (金 → 钅). Phono-semantic compound (形聲): semantic 钅 (“metal”) + phonetic 勾 – a metal hook. 勾 also has meaning of “hook”, from its semantic 勹, hence a metal (金) hook (勾, 勹).
钩 (radical 167 钅+4, 9 strokes, cangjie input 金心戈 (CPI) or 人心心戈 (OPPI) or XXX金心 (XXXCP), composition ⿰钅勾)
|For pronunciation and definitions of 钩 – see 鉤.
(This character, 钩, is the simplified form of 鉤.)