If you say that someone is blustering, you mean that they are speaking aggressively but without authority, often because they are angry or offended. `That's lunacy,' he blustered He was still blustering, but there was panic in his eyes. Bluster is also a noun. the bluster of the Conservatives' campaign
a violent gusty wind noisy confusion and turbulence; "he was awakened by the bluster of their preparations" blow hard; be gusty, as of wind; "A southeaster blustered onshore"; "The flames blustered