tongue-in-cheek

/T AH1 NG IH0 N CH IY0 K/
adjective
  1. 1

    Not intended seriously; jocular or humorous.

    โ€œHe gave a tongue-in-cheek explanation of why the sky was blue, offering a theory about some primordial discount on light blue paint.โ€

adverb
  1. 1

    With contempt.

  2. 2

    With irony.

    โ€œHe portrayed them tongue-in-cheek as great lawgivers, as Solons.โ€

Source: https://en.wiktionary.org/wiki/tongue-in-cheek