adjective / verb
dumb
DUHM/dʌm/
Lacking intellectual sophistication.
He makes a dumb mistake by sawing the branch supporting him.

Etymology
Old English dumb meant 'silent' or 'unable to speak'; the intelligence sense probably arose from interpreting nonresponse as incomprehension. The modern use for 'foolish' seems to reflect the influence of German dumm.
In context
i'm an idiot i'm a dumb bimbo i don't know what i'm talking about
More examples
- Leaving your keys in the car is a dumb idea.
- I feel dumb for missing such an obvious clue.
- The editor refuses to dumb down the article.
Forms
dumb · dumber · dumbest · dumbs · dumbed · dumbing