Answer in Quintagram not half odd (6)
I believe the answer is:
quaint
'odd' is the definition.
(thesaurus)
'answer in quintagram not half' is the wordplay.
'answer' becomes 'a' (abbreviation eg in Q and A).
'in' is an insertion indicator.
'not half' indicates taking half.
'quintagram' halved is 'quint'.
'a' inserted inside 'quint' is 'QUAINT'.
(Other definitions for quaint that I've seen before include "Picturesque" , "Attractively unusual or old-fashioned" , "Charmingly odd, old" , "Curious" , "Attractive, in an old-fashioned way" .)