Not made-to-measure (3-3-3)
I believe the answer is:
off-the-peg
'not made-to-measure' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for off-the-peg that I've seen before include "Ready-made, for immediate purchase" , "Not made-to-measure" , "Of clothes, bought ready to wear" , "(Of clothes) ready-to-wear" , "Of clothes, not made to measure, on the rack" .)