Simple Definition of sicko
: a person who does disturbing things that a person who is mentally normal would not do
Full Definition of sicko
: a person who is mentally or morally sick
Examples of sicko in a sentence
She was afraid to walk alone for fear some sicko might be lurking in the shadows.
<some sicko kidnapped and murdered as many as a dozen young women>
First Known Use of sicko
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Thesaurus: All synonyms and antonyms for "sicko"
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