Learn how to say Ostentatiously correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word ostentation:
the pretentious or showy display of wealth and luxury, designed to impress:
the office was spacious, but without any trace of ostentation
late Middle English: via Old French from Latin ostentatio(n-), from the verb ostentare, frequentative of ostendere ‘stretch out to view’