Adjective

(en-adj)

Marked by unthinking recklessness with disregard for danger; bold but rash; hotheaded

* {{quote-book

, year=1876 , author=Mark Twain , title=The Adventures of Tom Sawyer , chapter=6 citation , passage=The master’s pulse stood still, and he stared helplessly. The buzz of study ceased. The pupils wondered if this foolhardy boy had lost his mind.}}

* 2000 . Bill Bryson, In a Sunburned Country , p. 14:

In the middle distance several foolhardy souls in wet suits were surfing toward some foamy outbursts on the rocky headland...

Adjective

(en adjective)

careless, reckless, not exercising proper caution

* 1749, Henry Fielding, The History of Tom Jones, a Foundling

"You might have remained so still," replies Jones, "if you had not been unfortunate, I will venture to say incautious , in the placing your affections.

* 1912 , Stratemeyer Syndicate, Baseball Joe on the School Nine Chapter 1

"Yes, let 'Sister' Davis have a whack at it too," urged George Bland. Tom Davis, who was Joe Matson's particular chum, was designated "Sister" because, in an incautious moment, when first coming to Excelsior Hall, he had shown a picture of his very pretty sister, Mabel.