WordNet (r) 3.0 (2006):

professionalise
    v 1: become professional or proceed in a professional manner or
         in an activity for pay or as a means of livelihood [syn:
         professionalize, professionalise]
    2: make professional or give a professional character to;
       "Philosophy has not always been professionalized and used to
       be a subject pursued only by amateurs" [syn:
       professionalize, professionalise]