noun, masculine/pɔ̃.pɔ̃/plural: pompons
pompon (bundle of yarn, string, ribbon, etc.); culmination; climax; a very good or bad exemplar or end result
“c’est le pompon !” — That takes the cake!
Synonyms: comble, bouquet
First attested in 1556. Possibly from a root *pomp-, used to express roundness, or related to pompe.