Attractive old volunteers remain without answer (5)
I believe the answer is:
tasty
'attractive' is the definition.
(I've seen this before)
'old volunteers remain without answer' is the wordplay.
'old volunteers' becomes 'TA' (Territorial Army, former name of the Army Reserve).
'remain' becomes 'stay' (synonyms).
'without' indicates named letters should be taken away.
'answer' becomes 'a' (abbreviation eg in Q and A).
'stay' with 'a' removed is 'sty'.
'ta'+'sty'='TASTY'
(Other definitions for tasty that I've seen before include "Like nice grub" , "With a nice flavour" , "Scrumptious" , "Appetising, having pleasant flavour" , "Appetizing" .)