Source : Webster's Revised Unabridged Dictionary (1913)

Jeering \Jeer"ing\, a.
   Mocking; scoffing. -- n. A mocking utterance. --
   {Jeer"ing*ly}, adv.

Source : WordNet®

jeeringly
     adv : in a disrespectful jeering manner [syn: {mockingly}, {gibingly}]