on the down-low

Prepositional phrase

 * 1)  In secret.
 * I'll tell you, but keep it on the down-low.
 * 1)  Secretly sleeping with someone other than one's partner.
 * 2)   Publicly identifying as heterosexual but secretly having sex with other men.

Usage notes

 * Also used as a predicate.

Synonyms

 * see also Thesaurus:covert