Small fruit or piece of asparagus (5)
I believe the answer is:
spear
'piece of asparagus' is the definition.
(I've seen this in another clue)
'small fruit' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'fruit' becomes 'pear' (pear is a kind of fruit).
's'+'pear'='SPEAR'
'or' is the link.
(Other definitions for spear that I've seen before include "Shafted weapon for throwing or thrusting" , "stick" , "Weapon; asparagus stem" , "Spike" , "Long pointed weapon" .)