tiny bit, little bit
Vous exagérez un tantinet, non ?
You're exaggerating a little, aren't you?
— Moscou ne croit pas aux larmes (1980)
Un tantinet simple, mais son attrait est incontestable.
It's a bit simple, but its appeal is undeniable.
— Princess Bride (1987)
Je vous suggère de nettoyer un tantinet, avant que votre mère n'arrive ici.
I suggest you tidy up a bit before your mother gets here.