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Phrase(s): pack a punch
Go to pack a wallop and pack a punch
McGrawhill's American Idioms And Phrasal Verbs
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Also, pack a wallop. 1. Be capable of a forceful blow; also, deliver a forceful blow. For example, Knowing Bob could pack a wicked punch, they were careful not to anger him, or She swung her handbag, really packing a wallop. [Colloquial; c. 1920] 2. Have a powerful effect, as in That vodka martini packed a wallop. Thomas Wolfe had this figurative usage in a letter (c. 1938): "I think my play, The House, will pack a punch."
American Heritage Idioms