downlow

/D AW1 N L OW0/
adjective
  1. 1

    (of a person) Undercover or lying about one's identity.

  2. 2

    (of a man) Purporting to be heterosexual while engaged in sex with men.

Source: https://en.wiktionary.org/wiki/down%20low, https://en.wiktionary.org/wiki/downlow