One holds guy, perhaps, after ten pints knocked back (4,3)
I believe the answer is:
tent peg
'one holds guy' is the definition.
(guy can mean a rope securing a tent)
'perhaps after ten pints knocked back' is the wordplay.
'perhaps' becomes 'eg' (for example).
'after' says to put letters next to each other.
'pints' becomes 'pt' (abbreviation).
'knocked back' shows that the letters should be reversed in order.
'pt' in reverse letter order is 'tp'.
'ten'+'tp'='tentp'
'eg' put after 'tentp' is 'TENT-PEG'.
(Other definitions for tent peg that I've seen before include "Camping equipment" , "will hold a guy down" , "Guy's hooked on this" , "Fastener for guy" , "A guy could get attached to that" .)