Boast about row (4)
I believe the answer is:
crow
'boast' is the definition.
(crow is a kind of boast)
'about row' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa'**).
'c'+'row'='CROW'
(Other definitions for crow that I've seen before include "Make sound of cock - bird" , "Blow one's own trumpet" , "Native American -- bird" , "Gloat" , "Black bird; brag" .)