What does "whack" mean?

1. (to hit hard) to hit something or someone very hard, often with a loud noise. 2. (to murder) to kill someone, especially in a planned way by a criminal group. 3. (an attempt) a try or a chance at doing something. 4. (a loud hit) the sound or act of hitting something hard. 5. (backslash character) the name for the backslash symbol (\) used in computer paths. 6. (bad or lame) very bad, unfair, or disappointing.

whack — meaning, definition & examples

Word

01to hit hard

B2 · Upper Intermediate Informal

v. to hit something or someone very hard, often with a loud noise.

v. to strike something with a heavy, forceful blow. Transitive — requires a direct object.

“He whacked the ball with his racket and it flew over the fence.”

“The carpenter whacked the stubborn wooden peg with a mallet until it finally sat flush against the beam.”

Synonyms

hit strike smack thump

Antonyms

tap caress

02to murder

C1 · Advanced Slang

v. to kill someone, especially in a planned way by a criminal group.

v. to assassinate or murder someone, typically within the context of organised crime.

“In the movie, the mob boss ordered his men to whack the witness.”

“The screenplay depicts a gritty underworld where rivals are whacked over minor territorial disputes.”

Synonyms

assassinate bump off execute

03an attempt

B2 · Upper Intermediate Countable noun Informal

n. a try or a chance at doing something.

n. an attempt, turn, or opportunity to perform a task. Usually used in the phrase 'have a whack at'.

“I've never tried fixing a sink before, but I'll have a whack at it.”

“After several experts failed to solve the puzzle, the intern decided to take a whack at it during her lunch break.”

Synonyms

try attempt go shot

04a loud hit

B2 · Upper Intermediate Countable noun Informal

n. the sound or act of hitting something hard.

n. the physical act of a forceful strike or the resonant sound produced by such an impact.

“The book fell off the shelf with a loud whack on the floor.”

“The sudden whack of the branch against the windowpane startled everyone in the silent library.”

Synonyms

blowthwackbang

05backslash character

C2 · Proficiency Countable noun Computing Technical · Informal

n. the name for the backslash symbol (\) used in computer paths.

n. a verbal name for the backslash character (\), frequently used when dictating file paths or code.

“To find the file, type C whack users whack documents.”

“The administrator dictated the server path as 'double-whack production-one' to ensure the technician typed the backslashes correctly.”

Synonyms

backslash

06bad or lame

C1 · Advanced Slang

adj. very bad, unfair, or disappointing.

adj. of poor quality, contemptible, or socially unacceptable. Often spelled 'wack' but sometimes 'whack'.

“That new rule at school is totally whack.”

“The fans complained that the concert was whack because the lead singer forgot half the lyrics.”

Synonyms

lame rubbish terrible

Antonyms

cool excellent

The verb is transitive and requires a direct object. In informal British English, it can also mean to put or place something somewhere quickly.

“He believes that political change is still possible.” The world has now slipped seriously out of whack, she admits.”

The Guardian 15 Oct 2026

Uncertain. Originally Scottish; probably onomatopoeic, but compare Middle English thakken, from Old English þaccian (whence Modern thwack by conflation with whack). Sense 6 of the verb is likely a semantic loan from Malay hentam (“to strike; to do something carelessly”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.