The Collaborative International Dictionary of English v.0.48:
Prohibitive \Pro*hib"it*ive\, a. [Cf. F. prohibitif.] That prohibits; prohibitory; as, a tax whose effect is prohibitive. [1913 Webster]WordNet (r) 3.0 (2006):
prohibitive adj 1: tending to discourage (especially of prices); "the price was prohibitive" [syn: prohibitive, prohibitory]