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):
persuasively adv 1: in a persuasive manner; "this essay argues so persuasively..."