Boast, crow (4)
I believe the answer is:
brag
I believe this is a double definition.
'boast' is the first definition.
(I know that boast can be written as brag)
'crow' is the second definition.
(I know that crow can be written as brag)
(Other definitions for brag that I've seen before include "game, making > boast" , "Show off, crow" , "Card game - boast" , "boast; form of poker" , "game of bluff" .)