Grow together (7)
I believe the answer is:
accrete
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">grow together</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for accrete that I've seen before include "Build up" , "Get bigger" , "Care etc. (anag.)" , "Grow together, unite" , "Become attached" .)