- (US, idiomatic, slang, euphemistic) In secret.
- I'll tell you, but keep it on the down-low.
- (US, idiomatic, slang, euphemistic) Secretly sleeping with someone other than one's partner.
- (African American Vernacular, LGBT) (of a male) Publicly identifying as heterosexual but secretly having sex with other men.
- Also used as a predicate.
- see also Wikisaurus:covert