understatement
US /ˌʌn.dɚˈsteɪt.mənt/
UK /ˌʌn.dɚˈsteɪt.mənt/

1.
eufemismo, sottostima
the presentation of something as being smaller, worse, or less important than it actually is
:
•
To say it was difficult would be an understatement.
Dire che è stato difficile sarebbe un eufemismo.
•
His calm reaction was a huge understatement of his true feelings.
La sua reazione calma era un enorme eufemismo dei suoi veri sentimenti.