To say he's had a bad month would be a gross understatement.
It would be a gross understatement to say that these events did not have an impact on the school.
As it turned out, that proved to be a gross understatement.
"Her figure looks all right to me," Dad said, making a gross understatement.
I know, please believe me, and that is a gross understatement of the woman's character, too.
To say it was a long shot is a gross understatement.
But to call him a portrait artist is a gross understatement.
To say I wasn't a gun person was a gross understatement.
To say that he was frightened would be a gross understatement.
To say that he had lived the last two weeks in a state of high anxiety was a gross understatement.