Definitions

1. adjective

most eccentric or unconventional; most unusual or unexpected

“She thought her wackiest idea yet was to open a cat cafe.”

2. adverb

in an eccentric or unconventional manner

“He always dressed wackiest to the annual music festival.”

3. noun

a person who is eccentric or unconventional

“At the party, there was a wackiest who wore a bright pink wig.”