(n.) An inhabitant of a madhouse; a madman.

apish asinine balmy bananas barmy bats beany bedlamite befooled beguiled besotted bonkers brainless buffoonish buggy bughouse bugs cockeyed cracked crackers crazed crazy credulous cuckoo daffy daft dazed deranged dippy dizzy doting dotty dumb fatuitous flipped fond fool foolheaded foolish freaked-out fruitcakey fruity fuddled futile gaga goofy gulled haywire idiotic imbecile inane inept infatuated insane just plain nuts kooky loony loopy mad maniac maudlin moronic nuts nutty off the hinges off the track off the wall potty round the bend sappy screwball screwballs screwy senseless sentimental silly slaphappy stupid thoughtless wacky wet witless