Meaning of “outgrow” - Learner’s Dictionary

outgrow

verb [ T ] uk us /ˌaʊtˈɡrəʊ/ (past tense outgrew, past participle outgrown)
TOO BIG

to grow too big for something:

He's already outgrown these shoes.
The company has outgrown this building.
NOT SUITABLE

to develop so that something is not now suitable:

She's outgrown her current job and needs a new challenge.

(Definition of “outgrow” from the Cambridge Learner’s Dictionary © Cambridge University Press)