Nouns

(n)smasher, stunner, knockout, beauty, ravisher, sweetheart, peach, lulu, looker, mantrap, disha very attractive or seductive looking woman
(n)knockout, KO, kayoa blow that renders the opponent unconscious

Adjectives

(s)hard, knockout, severevery strong or vigorous“a hard left to the chin”, “a knockout punch”, “a severe blow”