oppugner

enUK

op·pugn

O0099500 (ə-pyo͞on′)tr.v. op·pugned, op·pugn·ing, op·pugns To oppose, contradict, or call into question.
[Middle English oppugnen, from Latin oppugnāre, to attack : ob-, against; see ob- + pugnāre, to fight with the fist; see peuk- in Indo-European roots.]
op·pugn′er n.