wacko

adj

1. (derogatory, informal, slang)Amusingly eccentric or irrational.

noun

1. (derogatory, slang)An amusingly eccentric or irrational person.

   ““Environmentalist wackos” — Mr. Limbaugh’s phrase — “want man to be responsible for it because they want to control your behavior,” the conservative host said on the show.”

intj

1. (British, dated)Hurrah!

   “"Wacko! There's a whole pile of letters for me," Jennings cried excitedly, hopping from one foot to the other.”