Learn English – What’s the English idiom/saying to describe that the chosen word is not correct

idiomspopular-refrains

I mean that the word used is too light or too subtle to describe the gravity of the situation?

For example (an artificial example): the tsunami starts, the incredibly big waves are coming to the shore and the person says
"Such big waves!"
But in reality "big" is too light to describe the tsunami. The word must be more exaggerating. So I want to say something like:
"You chose the word 'big', but it is too light to describe it" or "It's not the right word".
or "It's not the word". How to say it in a more compact form?
I tried to say "It's not the word" but only a few people understood me.

Best Answer

In some contexts, the word you're looking for is "understatement".

When done intentionally, it could be "irony".

Try this: "Big? That's an understatment!"

Irony: "I have a flight booked from NY to London. I get nervous flying over the big pond." (Atlantic Ocean)