pros·e·lyt·ize / ˈpräsələˌtīz/ • v. [tr.] convert or attempt to convert (someone) from one religion, belief, or opinion to another: the program did have a tremendous evangelical effect, proselytizing many | [intr.] proselytizing for converts | [as n.] (proselytizing) no amount of proselytizing was going to change their minds. ∎ advocate or promote (a belief or course of action): Davis wanted to share his concept and proselytize his ideas.DERIVATIVES: pros·e·lyt·iz·er n.