The Collaborative International Dictionary of English v.0.48:
Antimalarial \An`ti*ma*la"ri*al\ ([a^]n`t[i^]*m[.a]*l[=a]"r[i^]*al), a. Good against malaria. [1913 Webster]WordNet (r) 3.0 (2006):
antimalarial n 1: a medicinal drug used to prevent or treat malaria [syn: antimalarial, antimalarial drug]