foolish

UK: /ˈfuːlɪʃ/ US: /ˈfulɪʃ/ ,(fo̅o̅′lish)

WordReference Random House Learner's Dictionary of American English © 2026

fool•ish /ˈfulɪʃ/   adj. 

1. resulting from or showing a lack of good sense:
   a foolish prank.
2. lacking forethought or caution;
   appearing like a fool:
   felt foolish asking such a big favor.

fool•ish•ly, adv. 
fool•ish•ness, n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2026

fool•ish  (fo̅o̅′lish), adj. 

1. resulting from or showing a lack of sense;
   ill-considered;
   unwise:
   a foolish action, a foolish speech.
2. lacking forethought or caution.
3. trifling, insignificant, or paltry.

• Middle English folish, foolish. See fool¹, -ish¹ 1250–1300

fool′ish•ly, adv. 
fool′ish•ness, n. 
Synonyms

• 1, 2. senseless, vacant, vapid, simple, witless.
  Foolish, fatuous, silly, inane, stupid, asinine imply weakness of intellect and lack of judgment.
  Foolish implies lack of common sense or good judgment or, sometimes, weakness of mind:
  a foolish decision; The child seems foolish.
  Fatuous implies being not only foolish, dull, and vacant in mind, but complacent and highly self-satisfied as well:
  fatuous and self-important; fatuous answers.
  Silly denotes extreme and conspicuous foolishness; it may also refer to pointlessness of jokes, remarks, etc.:
  silly and senseless behavior; a perfectly silly statement.
  Inane applies to silliness that is notably lacking in content, sense, or point:
  inane questions that leave one no reply.
  Stupid implies natural slowness or dullness of intellect, or, sometimes, a benumbed or dazed state of mind; it is also used to mean foolish or silly:
  well-meaning but stupid; rendered stupid by a blow; It is stupid to do such a thing.
  Asinine originally meant like an ass; it applies to witlessly stupid conversation or conduct and suggests a lack of social grace or perception:
  He failed to notice the reaction to his asinine remarks.
• 1. imprudent, unreasonable, foolhardy, irrational; thoughtless, nonsensical, ridiculous, absurd, pointless, preposterous.

Collins Concise English Dictionary © HarperCollins Publishers::

foolish / ˈfuːlɪʃ/ adjective

1. unwise; silly
2. resulting from folly or stupidity
3. ridiculous or absurd; not worthy of consideration
4. lacking in intelligence
5. an archaic word for insignificant

ˈfoolishly adverb

ˈfoolishness noun