dastardly

/หˆdรฆstษ™dli/

IPA: /D AE1 S T ER0 D L IY0/

adjective
  1. 1

    In the manner of a dastard; marked by cowardice; pusillanimous

  2. 2

    Treacherous; given to backstabbing

adverb
  1. 1

    In a cowardly or treacherous fashion.

Source: https://en.wiktionary.org/wiki/dastardly