Past tense of hawk: to sell goods by calling out in the streets, or to hunt with a hawk.
From Old English 'hafoc' (hawk the bird) for the hunting sense, and from Middle Dutch 'hoekster' for the peddling sense. Both emerged as separate meanings but are spelled identically. The peddling sense developed because hawks were associated with aggressive pursuit, like street vendors pursuing customers.
Shakespeare's London was filled with 'hawkers' shouting in the streets, and the word 'hawk' meaning 'to sell aggressively' came directly from watching these vendors hunt for customers the way actual hawks hunt prey—persistence and boldness.
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