Process of becoming smaller (9)
I believe the answer is:
shrinkage
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">process of becoming smaller</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for shrinkage that I've seen before include "lessening" , "Gin shaker? (anag)" , "waste allowance" , "Process of becoming less" , "Process by which something becomes smaller" .)