Etymology
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foolhardy (adj.)

also fool-hardy, mid-13c., folhardi, from fol "fool" (see fool (n.1) + hardi "bold" (see hardy) hence "foolishly brave, bold without judgment or moderation." Compare Old French fol hardi. Related: foolhardiness (mid-13c.); Middle English had also as a noun foolhardiment (mid-15c.).

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audacity (n.)
early 15c., "boldness, courage, daring; vigor, animation," from Medieval Latin audacitas "boldness," from Latin audacis genitive of audax "bold, daring; rash, foolhardy" (see audacious). In English, the meaning "presumptuous impudence," implying contempt of moral restraint, is from 1530s.
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enterprising (adj.)
"eager to undertake, prompt to attempt," 1610s, present-participle adjective from the verb enterprise (late 15c.), from the noun enterprise. Until mid-19c. (at least in Britain) mostly in a bad sense: "scheming, ambitious, foolhardy." Earlier (1560s) as a verbal noun meaning "action of undertaking."
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audacious (adj.)

1540s, "confident, intrepid, daring," from French audacieux, from audace "boldness," from Latin audacia "daring, boldness, courage," from audax "brave, bold, daring," but more often "bold" in a bad sense, "rash, foolhardy," from audere "to dare, be bold." In English, the bad sense of "shameless, unrestrained by propriety" is attested from 1590s. Related: Audaciously; audaciousness.

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