1. 
[syn: persuasiveness, strength]
The Collaborative International Dictionary of English v.0.48:
Persuasive \Per*sua"sive\, n.
   That which persuades; an inducement; an incitement; an
   exhortation. -- Per*sua"sive*ly, adv. --
   Per*sua"sive*ness, n.
   [1913 Webster]
WordNet (r) 3.0 (2006):
persuasiveness
    n 1: the power to induce the taking of a course of action or the
         embracing of a point of view by means of argument or
         entreaty; "the strength of his argument settled the matter"
         [syn: persuasiveness, strength] [ant:
         unpersuasiveness]