/ ˈblʌstə(r); NAmE / verb
1.
to talk in an aggressive or threatening way, but with little effect :
[ v speech ]
'I don't know what you're talking about,' he blustered.
[ v ]
a blustering bully
2.
[ v ] ( of the wind ) to blow violently
► blus·ter noun [ U ]:
I wasn't frightened by what he said—it was all bluster.
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WORD ORIGIN
late Middle English : ultimately imitative.