The word 'swagger' first appeared in English in the early 16th century, originally meaning 'to strut in a defiant or insolent manner'. Its core is the verb 'swag', an older term meaning 'to sway or swing', which is thought to be of Scandinavian origin, related to the Norwegian dialect word 'svagra' (to sway unsteadily). The '-er' suffix in 'swagger' is a frequentative element, indicating a repeated or intensive action—thus, a repeated, swinging, boastful motion. The addition of the present participle suffix '-ing' transforms the action into an adjective, describing someone engaged in this arrogant, rolling gait or boastful behavior.

Structure: swagger (to strut) + ing (adjective/participle suffix) swagger: Likely a frequentative form from the verb 'swag' (to sway), of uncertain origin, possibly Scandinavian or Low German. Functions as the core verb root. ing: A suffix from Old English '-ende', '-inge', used to form present participles and adjectives from verbs.