blackguard

Short definition from Wiktionary

Noun

1. 1
   The lowest servant in a household charged with pots, pans, and other kitchen equipment.
2. 2
   An unprincipled, contemptible person; an untrustworthy person.
3. 3
   A man who uses foul language in front of a woman (typically a woman of high standing).

Verb

1. 1
   To revile or abuse in scurrilous language.
2. 2
   To act like a blackguard; to be a scoundrel.