understating

/AH1 N D ER0 S T EY0 T IH0 NG/
verb
  1. 1

    To state (something) with less completeness than needed; to minimise or downplay.

  2. 2

    To state (something) with a lack of emphasis, in order to express irony.

  3. 3

    To state a quantity that is too low.

Source: https://en.wiktionary.org/wiki/understate, https://en.wiktionary.org/wiki/understating