English
threenager
Blend of three + teenager.
Proto-Indo-European *tréyes
Proto-Germanic *þrīz
Proto-West Germanic *þrīʀ
Old English þrī
Middle English thre
English three
Today it means
noun A rebellious and strong-willed three-year-old.
Language periods are conventional ranges, not dates for this word.
Etymograph / threenager