Etymology
Advertisement
weirdo (n.)
"strange person," 1955, from weird. Compare earlier Scottish weirdie "young man with long hair and a beard" (1894).
Related entries & more 
Advertisement
sicko (n.)
1977, from sick (adj.) in the mental sense + ending as in weirdo. Sickie "a pervert" is attested from 1972; sicknik (1959) "pervert, obscene comedian" (applied to Lenny Bruce) has fad ending -nik.
Related entries & more