Adjective
1. slow to learn or understand; lacking intellectual acuity;
"so dense he never understands anything I say to him""never met anyone quite so dim""although dull at classical learning, at mathematics he was uncommonly quick"- Thackeray"dumb officials make some really dumb decisions""he was either normally stupid or being deliberately obtuse""worked with the slow students"2. unable to speak temporarily;
"struck dumb""speechless with shock"3. lacking the power of human speech;
"dumb animals"4. unable to speak because of hereditary deafness