Singular boast about keeping figure in field (9)
I believe the answer is:
scarecrow
'figure in field' is the definition.
(I've seen this before)
'singular boast about keeping' is the wordplay.
'singular' becomes 's' (abbreviation sometimes used in dictionaries).
'boast' becomes 'crow' (to crow about something is to boast about it).
'about' means one lot of letters go next to another.
'keeping' becomes 'care' (I've seen this in other clues).
'crow' after 'care' is 'carecrow'.
's'+'carecrow'='SCARECROW'
(Other definitions for scarecrow that I've seen before include "Batman villain" , "One in 5d's party" , "Bird frightener" , "he's shabbily dressed" , "fixture in field ..." .)