Grow into (6)
I believe the answer is:
become
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">grow into</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for become that I've seen before include "Grow to be" , "Evolve into; suit" , "Suit; turn into" , "Flatter" , "Metamorphose into it" .)