swagger (v.)

1580s, "to strut in a defiant or insolent manner;" earliest recorded usages are in Shakespeare ("Midsummer Night's Dream," "2 Henry IV," "King Lear"), probably a frequentative form of swag (v.) "to sway." Meaning "to boast or brag" is from 1590s. Related: Swaggered; swaggering. The noun is attested from 1725.

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Definitions of swagger from WordNet
swagger (v.)
to walk with a lofty proud gait, often in an attempt to impress others;
Synonyms: tittup / ruffle / prance / strut / sashay / cock
swagger (v.)
discourage or frighten with threats or a domineering manner; intimidate;
Synonyms: browbeat / bully
swagger (v.)
act in an arrogant, overly self-assured, or conceited manner;
Synonyms: bluster / swash
swagger (n.)
an itinerant Australian laborer who carries his personal belongings in a bundle as he travels around in search of work;
Synonyms: swagman / swaggie
swagger (n.)
a proud stiff pompous gait;
Synonyms: strut / prance
swagger (adj.)
(British informal) very chic;
Synonyms: groovy