Unanticipated blow

• Unexpected blow, or refreshment at a party for Dracula?
• Sneaky blow
• Unexpected hit
• Drink served to a chump?
• Beverage for a get-rich-quick guru?
• Sweet drink for Dracula?
• Unexpected blow
• Sudden setback — surprise blow from behind

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
also sucker-punch , 1926, from sucker in the "dupe" sense + punch (n.3). Figurative use by 1929. As a verb by 1942. Related: Sucker-punched .