Counteract
Pronunciation : Coun`ter*act" (koun`tr-kt")
Part of Speech : v.
Definition : Defn: To act in opposition to; to hinder, defeat, or frustrate, by contrary agency or influence; as, to counteract the effect of medicines; to counteract good advice.
t. [imp. & p. p. Counteracted; p. pr. & vb. n. Counteracting.]
Source : Webster's Unabridged Dictionary, 1913