A person who performs showy or dramatic actions to impress others rather than for genuine reasons.
From 'grandstand' (a large stand at sports events with good seating) + '-er' (agent noun suffix). The term evolved metaphorically in early 1900s from the idea of performing for the audience in the grandstands.
Politicians and athletes alike have been accused of 'grandstanding' since the term entered common usage around 1900—it reveals our deep human instinct to perform for an audience, even when it might not serve the actual purpose at hand.
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