What is Screwball?
1.
an idiot who's insane
That's one crazy screwball
2.
a babbling or ranting fool
that ranting evangelist sure is a screwball
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3.
1) A youth with a traumatic or bad childhood/past which causes problems in the present
2) A caller of the nationally syndicated radio show "LoveLine", usually having kids at an unhealthily young age.
"Listen, all you screwballs out there, stop having children!"
See