To get some wine by the pint seems unsuitable (5)
I believe the answer is:
inept
'unsuitable' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for inept that I've seen before include "pointless" , "Standard required in a piece of work (colloq.)" , "Foolish" , "Silly or senseless" , "Lacking skill" .)