1dumb 
/ˈdʌm/ adjective
dumb·er; dumb·est /ˈdʌm/ adjective 1 informal a : not showing or having good judgment or intelligence : stupid or foolish
▪ I'm not dumb enough to believe that. ▪ It was a dumb idea in the first place. ▪ He just stood there with a dumb grin on his face. ▪ This is one of the dumbest TV shows I've ever seen. ▪ She played/acted dumb [=pretended to know or understand less than she really did] so we would assign her the easier tasks.
b : not requiring or resulting from intelligence
▪ It was dumb luck that we found this place at all. ▪ His success is just a matter of dumb luck. 2 a : not able to speak especially after being shocked or surprised
▪ I was struck dumb [=made speechless] by the surprise. — see also dumbstruck
b old-fashioned + often offensive : not having the ability to speak
▪ He was born deaf and dumb.
▪ I'm not dumb enough to believe that. ▪ It was a dumb idea in the first place. ▪ He just stood there with a dumb grin on his face. ▪ This is one of the dumbest TV shows I've ever seen. ▪ She played/acted dumb [=pretended to know or understand less than she really did] so we would assign her the easier tasks.
b : not requiring or resulting from intelligence
▪ It was dumb luck that we found this place at all. ▪ His success is just a matter of dumb luck.
▪ I was struck dumb [=made speechless] by the surprise. — see also dumbstruck
b old-fashioned + often offensive : not having the ability to speak
▪ He was born deaf and dumb.
— dumb·ly adverb
▪ He stared dumbly at the test.
▪ He stared dumbly at the test.
— dumb·ness noun [noncount] informal
▪ The movie's dumbness [=stupidity] is actually pretty funny.
▪ The movie's dumbness [=stupidity] is actually pretty funny.
