Become too large for (7)
I believe the answer is:
outgrow
'become too large for' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for outgrow that I've seen before include "Leave (something) behind as one matures" , "Get too big for" , "Become too big for" , "excel in development" , "Develop faster or become taller than" .)