As nouns the difference between foolishness and dumbass
is that foolishness
is (uncountable) the state of being foolish while dumbass
is (us|vulgar|slang) a person marked by stupidity or foolishness.
As a adjective dumbass is
(uncountable) The state of being foolish.
(countable) A thing or event that is foolish, or an absurdity.
* imprudence, folly
* extravagance, irresponsibility
* indiscretion, absurdity
(US, vulgar, slang) A stupid or foolish person.
- The dumbass walked off with my car keys and left me hers.
* See also
- That dumbass driver ruined my car!