contrafactual,a.Philos.|ˌkɒntrəˈfækt(j)uːəl| [f. contra- + factual a.] = counterfactual a. 1950W. V. Quine Methods of Logic (1952) i. iii. 14 The contrafactual conditional; e.g.: If Eisenhower had run, Truman would have lost.1961A. C. Ewing in I. Ramsey Prospect for Metaphysics ii. 48 A contrafactual conditional.