/ ˈʌndəsteɪtmənt; NAmE -dərs-/ noun
1.
[ C ] a statement that makes sth seem less important, impressive, serious, etc. than it really is :
To say we were pleased is an understatement (= we were extremely pleased) .
'These figures are a bit disappointing.' 'That's got to be the understatement of the year .'
2.
[ U ] the practice of making things seem less impressive, important, serious, etc. than they really are :
typical English understatement
He always goes for subtlety and understatement in his movies.
OPP overstatement