legitimatize

from WordNet (r) 3.0 (2006)

legitimatize
    v 1: make legal; "Marijuana should be legalized" [syn:
         {legalize}, {legalise}, {decriminalize}, {decriminalise},
         {legitimize}, {legitimise}, {legitimate}, {legitimatize},
         {legitimatise}] [ant: {criminalise}, {criminalize},
         {illegalise}, {illegalize}, {outlaw}]

from The Collaborative International Dictionary of English v.0.48

Legitimatize \Le*git"i*ma*tize\ (-t[imac]z), v. t.
   To legitimate.
   [1913 Webster]