usage: 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"
4. slow (vs. fast)
usage: (used of timepieces) indicating a time earlier than the correct time; "the clock is slow"
usage: so lacking in interest as to cause mental weariness; "a boring evening with uninteresting people"; "the deadening effect of some routine tasks"; "a dull play"; "his competent but dull performance"; "a ho-hum speaker who couldn't capture their attention"; "what an irksome task the writing of long letters is"- Edmund Burke; "tedious days on the train"; "the tiresome chirping of a cricket"- Mark Twain; "other people's dreams are dreadfully wearisome"
6. dull, slow, sluggish, inactive (vs. active)
usage: (of business) not active or brisk; "business is dull (or slow)"; "a sluggish market"