确切
quèqiè · HSK 7
accurate
🎯 确切 = 确 certain/firm + 切 close/exact = nailed-down precise
确 carries the sense of solid certainty (as in 确实 indeed); 切 means close-fitting or exact (as in 切合 to fit closely). Together they stack two precision words, so 确切 means accurate and unambiguous, leaving no gap.
切 — 七 (phonetic) + 刀 (knife radical)
切 is a semantic-phonetic compound: 刀 'knife' gives the meaning of cutting, while 七 supplies the sound. The original sense was to slice or cut with a blade. From there it extended figuratively to 'close to' (as in pressed against) and 'urgent/earnest', as in 切实.