1) Absurd 2) Bananas 3) Crazy 4) Insane 5) Loco 6) Mad as a march hare 7) Nuts 8) Nutty 9) Odd 10) Ogchlsh 11) Wacko 1) Absurdly impractical 2) Behaving bizarrely 3) Crazy 4) Cuckoo 5) Cuckoo in the head 6) Disconcertingly peculiar 7) Eccentric 8) Insane 9) Laughably odd 10) Not behaving normally 11) Nuts 12) Nutso 13) Off the wall 14) Ridiculously odd 15) Screw-loose 
Screwy is slang for slightly intoxicated; tipsy.