Stop at holding mug the wrong way (5)
I believe the answer is:
abort
'stop' is the definition.
(I've seen this before)
'at holding mug the wrong way' is the wordplay.
'holding' is an insertion indicator.
'mug' becomes 'rob' (I've seen this in other clues).
'the wrong way' says the letters should be written backwards.
'rob' written backwards gives 'bor'.
'at' placed around 'bor' is 'ABORT'.
(Other definitions for abort that I've seen before include "Cut short" , "[FINISH] prematurely" , "Call off (mission) because of problem" , "Stop prematurely" , "End prematurely" .)