An eccentric, crazy or foolish person.
Someone addicted to crack cocaine (i.e. a drug addict).
Eccentric or impractical.
Someone perceived as odd, eccentric, and/or extreme.
Someone with crazy or extreme political views (especially extreme conservative views).
A member of the air force (in a town that hosts a USAF installation).
A mentally ill homeless person.
A deciduous tree of the genus Pterocarya native to Asia.