Both Uses

ostentatious
in
Identical, by Ellen Hopkins
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But Tonight Will Be Perv-Free Hugged by my ostentatiously thick mattress, falling fast, faster toward blessed sleep, or in my case, more likely the sleep of the damned, the space behind my eyes is covered by a dark collage.†
Chpt 21.

ostentatiously = in a manner intended to attract notice and impress others
Some, like Mick, wear it puffed up, peacocks strutting ostentation in lieu of real substance.†
Chpt 25. *

ostentation = actions intended to attract notice and impress others

Definitions:

(1) (ostentatious)
intended to attract notice and impress others -- especially with wealth in a vulgar way
(2) (meaning too rare to warrant focus)