Good space for union man? (5)
I believe the answer is:
groom
'union man?' is the definition.
(I've seen this in another clue)
'good space' is the wordplay.
'good' becomes 'g' (abbreviation).
'space' becomes 'room' (enough space or room to do something).
'g'+'room'='GROOM'
'for' acts as a link.
(Other definitions for groom that I've seen before include "One at wedding" , "Man in stable (about to be married?)" , "Prepare; one getting wed" , "Coach" , "school" .)