show up as

show (someone or something) up as (something)

To reveal someone's or something's true nature, character, or properties. The books shows up the CEO as a megalomaniac only concerned with increasing his own wealth and power. The senator showed the legislation up as an attempt to enrich the nation's wealthiest citizens.
See also: show, up
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

show someone up as something

to reveal that someone is really something (else). The investigation showed her up as a fraud. The test showed up the candidate as unqualified.
See also: show, up
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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