What Does Wackadoodle Mean?

This was a question that I was asking myself while watching the show The Antonio Treatment. I thought it meant weird or was a fun name for all natural diet pills. Apparently it's slang. However, on the show Antonio uses it to describe crazy situations or ideas. However according to several slang dictionaries it actually is a person who is a crazy as in "That wackadoodle tried to spell it whackadoodle". Yes, I really did try to spell it that way but how was I supposed to know? Technically it's not a word so I can spell it however I want.