adjective/zɛ̃.zɛ̃/
zinzin is masculine or feminine depending on context in French.
bonkers, cracked; like crazy, so much; buttocks
“J'aimerais trop de zinzin apprendre cette langue.” — I'd like to learn that language so much.
Uncertain, probably of onomatopoeic origin. Or maybe from German Wahnsinn or Dutch waanzin.