You boast with your words. You swagger with your walk.
Both words describe someone who is far too pleased with themselves, so children tend to swap them. The difference is which part of the body is doing the showing off.
Boasting is talking. A boy who tells the whole class, three times before lunch, that he scored the winning goal is boasting. So is someone who keeps mentioning how many sweets they got at the party.
Swaggering is walking. The same boy crossing the playground the next morning with his chest puffed out and his arms swinging is swaggering. He does not need to say a word: the proud walk says it for him.
To talk too proudly about yourself or what you own.
Similar: brag, crow
To walk in a proud, show-off way; or that proud way of walking.
Similar: strut, parade, boast
Comprehension questions often ask how a writer shows a character's arrogance. Spotting that swagger is a description of movement, not speech, helps a child explain the writer's choice rather than just repeating that the character is showing off.
Definitions and example sentences on this page are the ones a child sees inside Wordrealm, taken from our list of over 1,100 words. It is free to browse, with nothing to sign up for.
Plain-English guides to each test, from the councils’ own pages: Kent Test · Medway Test · Bucks Secondary Transfer Test