About a pound extra for spirits (6)
I believe the answer is:
morale
'spirits' is the definition.
(thesaurus)
'about a pound extra' is the wordplay.
'about' means one lot of letters goes inside another.
'pound' becomes 'l'.
'extra' becomes 'more' (I've seen this before).
'a'+'l'='al'
'al' put into 'more' is 'MORALE'.
'for' is the link.
(Other definitions for morale that I've seen before include "Strength of purpose" , "Feeling of well-being" , "Mood" , "Esprit de corps" , "external confidence" .)