Mean it's the wrong size (5)
I believe the answer is:
tight
'mean' is the definition.
(both can mean miserly)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for tight that I've seen before include "Fast - affected by drink" , "Firmly fastened; drunk" , "Mean; tipsy" , "Strictly imposed; drunk" , "Constricted - intoxicated" .)