A stream of water or liquid sprayed on the body for washing, or informally, an unpleasant or obnoxious person.
From French 'douche,' derived from Italian 'doccia' meaning a water pipe or conduit. The term originally referred to a shower of water used for bathing in 18th-century Europe, and later developed the slang meaning for a rude person.
The French and Italians had such a specific word for this bathing method that English borrowed it wholesale—but centuries later, people started using 'douche' as an insult, probably because it sounded funny and vaguely disparaging!
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