pretentious or conspicuous show, as of wealth or importance; display intended to impress others.
2.
Archaic.the act of showing or exhibiting; display.
Origin: 1425–75;late Middle Englishostentacioun < Middle Frenchostentation < Latinostentātiōn- (stem of ostentātiō), equivalent to ostentāt(us) past participle of ostentāre to display, exhibit, frequentative of ostendere to present, display (equivalent to os-, var of ob-ob- + ten(dere) to stretch + -t- frequentative suffix + -ātus-ate1) + -iōn--ion
mid-15c., from M.Fr. ostentation (mid-14c.), from L. ostentationem (nom. ostentatio) "vain display," from ostentatus, pp. of ostentare "to display," frequentative of ostendere (see ostensible).