(transitive) to exhibit or display so as to invite admiration
2.
(intransitive) (informal) to behave in such a manner as to make an impression
noun
3.
(informal) a person who makes a vain display of himself
Word Origin and History for show-off
n.
1776, "a display;" see show (v.) + off (adv.). From 1801 as "a deliberate and ostentatious display;" in reference to the person who makes such a display, attested from 1924. The verbal phrase is first recorded 1793 as "make a conspicuous and obvious display." Noun showing-off is from 1874.
Slang definitions & phrases for show-off
show-off
noun
A person who habitually shows off; hot dog, showboat: Speedo swimsuit and a globe tied to his shoulder. Show-off