The Collaborative International Dictionary of English v.0.48:
Sophistic \So*phis"tic\, Sophistical \So*phis"tic*al\, a. [L. sophisticus, Gr. ?: cf. F. sophistique.] Of or pertaining to a sophist; embodying sophistry; fallaciously subtile; not sound. [1913 Webster] His argument . . . is altogether sophistical. --Macaulay. [1913 Webster] -- So*phis"tic*al*ly, adv. -- So*phis"tic*al*ness, n. [1913 Webster]