|1.||[ adjective ] slow to learn or understand; lacking intellectual acuity|
|Synonyms:||slow dull obtuse dim dense|
"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"
|2.||[ adjective ] lacking the power of human speech|
|3.||[ adjective ] unable to speak temporarily|
"struck dumb" "speechless with shock"
|4.||[ adjective ] unable to speak because of hereditary deafness|