A time volunteers at home accomplish (6)
I believe the answer is:
attain
'accomplish' is the definition.
(synonyms)
'a time volunteers at home' is the wordplay.
'time' becomes 't' (abbreviation).
'volunteers' becomes 'TA' (abbreviation for Territorial Army).
'at home' becomes 'in' (similar in meaning).
'a'+'t'+'ta'+'in'='ATTAIN'
(Other definitions for attain that I've seen before include "Reach (a particular age)" , "Gain with effort" , "Fulfil" , "Reach, get there as with ambition" , "Reach with effort" .)