<p><strong>Verb</strong></p><ul><li>(used with object)<ul><li>to strike with a smart, resounding blow or blows.</li><li>Slang. to divide into or take in shares (often followed by up): Whack the loot between us two.</li></ul></li></ul><p><strong>Noun</strong></p><ul><li>a smart, resounding blow: a whack with his hand.</li><li>Informal. a trial or attempt: to take a whack at a job.</li><li>Slang. a portion or share.</li></ul><p><strong>Verb Phrase</strong></p><ul><li>Slang. to produce quickly or, sometimes, carelessly: She whacks out a short story every week or so.</li><li>to cut off or separate with a blow: The cook whacked off the fish's head.</li><li>Slang: Vulgar. to masturbate.</li></ul>