Belgium· hard· informal
mordre sur sa chique
“to bite on one's chewing tobacco”
Meaning
To hold back a strong emotion
Explanation
Used when someone grits their teeth and swallows their anger, sadness or impatience rather than showing it.
Example
Le patron a encore annulé ses vacances, mais elle a mordu sur sa chique et n'a rien laissé paraître.
The boss cancelled her holiday again, but she gritted her teeth and didn't let it show.
Origin
A chique is a plug of chewing tobacco, something you clamp down on rather than let go, which made it a natural stand-in for gritting your teeth through a feeling instead of letting it out.
Source