whack
1. [ verb ] hit hard
Synonyms: wallop whop wham
Examples:

"The teacher whacked the boy"

Related terms: hit wallop beating
2. [ noun ] the sound made by a sharp swift blow
Related terms: sound
3. [ noun ] the act of hitting vigorously
Synonyms: belt rap whang knock
Examples:

"he gave the table a whack"

Related terms: blow knock rap whang
Similar spelling:   whacky
  whacko
  whisk
  which
  whisky
  whiskey