Meaning of “stupid” - Learner’s Dictionary

stupid

adjective us uk /ˈstjuːpɪd/
SILLY

B1 silly or not intelligent:

That was a really stupid thing to do.
How could you be so stupid?

More examples

ANNOYING [ always before noun ] informal

used to show that you are annoyed about something which is causing a problem:

I can never get this stupid machine to work!
stupidity noun [ U ] us uk /stjuːˈpɪdəti/
stupidly adverb

(Definition of “stupid” from the Cambridge Learner’s Dictionary © Cambridge University Press)