whacky
1. [ adjective ] informal or slang terms for mentally irregular
Synonyms: balmy barmy bats batty bonkers buggy cracked crackers daft dotty fruity haywire kookie kooky loco loony loopy nuts nutty round_the_bend wacky around_the_bend
Examples:

"it used to drive my husband balmy"

Related terms: insane
2. [ adjective ] pungent adjectives of disesteem
Synonyms: silly wacky sappy cockamamy unreasonable goofy zany cockamamie
Examples:

"gave me a cockamamie reason for not going" "wore a goofy hat" "a silly idea" "some wacky plan for selling more books"

Related terms: colloquialism foolish
Similar spelling:   whack
  whisky
  whacko
  wacky
  whisk
  which