Definition of "spank"

verb:
- To beat, smack or slap a person's buttocks, with the bare hand or other object, as punishment, gesture or form of sexual interaction.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- To soundly defeat, to trounce.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
noun:
- An instance of spanking, separately or part of a multiple blows-beating; a smack, swat or slap.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License