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bravo [bravo 词源字典]: as an exclamation, "well done!," 1761, from Italian bravo, literally "brave" (see brave (adj.)). Earlier it was used as a noun meaning "desperado, hired killer" (1590s). Superlative form is bravissimo.
It is held by some philologists that as "Bravo!" is an exclamation its form should not change, but remain bravo under all circumstances. Nevertheless "bravo" is usually applied to a male, "brava" to a female artist, and "bravi" to two or more. ["Elson's Music Dictionary," 1905]
[bravo etymology, bravo origin, 英语词源]
well-done (adj.): c. 1200, "wise, prudent," from well (adv.) + done. Meaning "thoroughly cooked," in reference to meat, is attested from 1747. Well done! as an exclamation of approval is recorded from mid-15c.
macte: "Expressing approval, encouragement, or good will: ‘all praise to you!’, ‘well done!’, ‘bravo!’; ‘good luck!’", Late 16th cent.; earliest use found in Gabriel Harvey (c1552–1631), scholar and writer. From classical Latin macte, vocative of mactus honoured, extolled (used, frequently in fixed phrases, with estō may you be, either expressed or implicit), probably the past participle of an unrecorded verb *magere, cognate with magnus great.