Meaning of “show off” - Learner’s Dictionary

show off

phrasal verb with show uk us /ʃəʊ/ verb (past tense showed, past participle shown)

B2 to try to make people admire your abilities or achievements in a way which other people find annoying:

He was the kind of kid who was always showing off to his classmates.

(Definition of “show off phrasal verb, verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)