insane

adj.

[1]

mad , demented , psychotic , schizophrenic , schizoid , non compos mentis , manic , maniacal , lunatic , deranged , unbalanced , psychoneurotic , neurotic , eccentric , crazy , of unsound mind , crazed , unhinged , out of one's mind/head , mad as a hatter/a March hare , quirky , (Colloq) round the bend/twist , off one's rocker/chump , loopy , loony , certifiable , mental , screwy , dotty , cuckoo , not all there , not have all one's marbles , off-the-wall , out of it , (Brit) potty , (Slang) daft , nutty (as a fruit cake) , nuts , spaced out , spacy , batty , have bats in one's belfry , not right upstairs , barmy (in the crumpet) , crackers , have a screw loose , schizo , (Brit) bonkers , (US) bugs , bughouse , loco , crazy as a bedbug , (gone) off the deep end , kooky , kinky , out to lunch

[2]

stupid , harebrained , mad , dumb , dull , silly , asinine , ridiculous , idiotic , irrational , absurd , fatuous , ludicrous , foolish , nonsensical , irresponsible , reckless , wild , imbecilic , moronic , feeble-minded , hare-brained , addle-pated , addle-brained , scatterbrained , thimble-witted , attocerebral , (Brit) gormless , (Colloq) nutty , screwy , crazy