Not large (6)
I believe the answer is:
little
'not large' is the definition.
('little' is the opposite to 'large')
This is all the clue.
(Other definitions for little that I've seen before include "Fairies and leprechauns?" , "` `...... pitchers have big ears' '" , "'A . . . . . . knowledge is a dangerous thing'" , "Teensy-weensy" , "Wee; minute" .)