Stiffened with starch (a stiff substance made from plant starches), or stiff and formal in manner; the past tense of 'starch.'
From Old English stearc (strong or stiff), related to German 'stark' (strong); later came to mean treating fabric with the starch substance, which made it rigid.
In Victorian times, people loved starched collars so stiff they could almost stand up on their own—but they were terrible because the starch would crack and poke your neck, showing that fashion has always been willing to sacrifice comfort for looking proper.
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