The Collaborative International Dictionary of English v.0.48:
Refutal \Re*fut"al\ (r?*f?t"al), n. Act of refuting; refutation. [1913 Webster]WordNet (r) 3.0 (2006):
refutal n 1: the act of determining that something is false [syn: falsification, falsifying, disproof, refutation, refutal]