Speak boastfully (4)
(Other definitions for brag that I've seen before include "game of bluff" , "'Show off, boast (4)'" , "Card game, like poker" , "Talk boastfully" , "Boast, exaggerate" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">speak boastfully</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for bluster that I've seen before include "Brag (to hide fear)" , "Show off" , "Talk aggressively with empty threats" , "Loud aggressive talk" , "Speak boastfully" .)