Pick up a good spare (5)
I believe the answer is:
glean
'pick up' is the definition.
(I've seen this before)
'a good spare' is the wordplay.
'a good' becomes 'g' (abbreviation).
'spare' becomes 'lean' (similar in meaning).
'g'+'lean'='GLEAN'
(Other definitions for glean that I've seen before include "Gather (info or the harvest)" , "Angle for harvest" , "Pick up (information)" , "Pull together from various sources" , "Gather remnants of corn" .)