pretentiousness vs ostentatiousness

pretentiousness and ostentatiousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
pretentiousness	Yes	No	No	No
ostentatiousness	Yes	No	No	No

As nouns, pretentiousness and ostentatiousness are synonyms defined as:

pretentiousness and ostentatiousness: lack of elegance as a consequence of being pompous and puffed up with vanity

Other synonyms of pretentiousness include inflation, ostentation, pomposity, pompousness, puffiness, splashiness.

pretentiousness (noun)	ostentatiousness (noun)
the quality of being pretentious (behaving or speaking in such a manner as to create a false appearance of great importance or worth)	lack of elegance as a consequence of being pompous and puffed up with vanity
lack of elegance as a consequence of being pompous and puffed up with vanity