1. 
[syn: outlaw, criminalize, criminalise, illegalize, illegalise]
The Collaborative International Dictionary of English v.0.48:
Illegalize \Il*le"gal*ize\, v. t. [imp. & p. p. Illegalized;
   p. pr. & vb. n. Illegalizing.]
   To make or declare illegal or unlawful.
   [1913 Webster]
WordNet (r) 3.0 (2006):
illegalize
    v 1: declare illegal; outlaw; "Marijuana is criminalized in the
         U.S." [syn: outlaw, criminalize, criminalise,
         illegalize, illegalise] [ant: decriminalise,
         decriminalize, legalise, legalize, legitimate,
         legitimatise, legitimatize, legitimise, legitimize]