To frighten or alarm someone suddenly; to cause fear or terror.
From Old English 'afryhtan,' with Germanic roots. The 'a-' prefix means 'to' and 'fright' comes from 'fryht' (fear). It's been used since before 1000 AD.
Shakespeare used 'affright' constantly in his plays to create an old-fashioned, dramatic feeling—it sounds scarier and more theatrical than just saying 'frighten,' which is probably why it stuck around in poetic English.
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