Disturbed, wrinkled, or made messy; also emotionally upset or annoyed.
From the verb 'ruffle,' which comes from Middle Dutch 'ruffelen,' meaning to wrinkle or make rough. The word originally referred to physically disturbing feathers or fabric, then expanded to describe emotional states.
Ruffled feathers literally meant birds were upset—that's where we get the phrase! Animals telegraph their emotions through their appearance, and English speakers noticed this pattern so much they borrowed it as a metaphor.
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