blague
Mendacious boasting that lacks seriousness; falsehood or humbug, especially when it is told mockingly or without the expectation that anyone believes it.
countable, uncountable
The difference is this: one may be obliged to maintain a falsehood from feelings of pride or self-respect, but a blague can be given up without a scruple.
Where it comes from
Borrowed from French blague. Doublet of belly.
Adapted from the Wiktionary entry blague (CC BY-SA 4.0).