Make small (8)
I believe the answer is:
belittle
'make small' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for belittle that I've seen before include "Dismiss (something) as unimportant" , "Make small" , "Humiliate" , "Disparage, run down" , "Denigrate, disparage" .)