Source : Webster's Revised Unabridged Dictionary (1913)

Self-assertive \Self`-as*sert"ive\, a.
   Disposed to self-assertion; self-asserting.

Source : WordNet®

self-assertive
     adj 1: confidently aggressive; "too assertive as a salesman"; "his
            self-assertive and unflagging energy" [syn: {assertive},
             {self-asserting}]
     2: offensively self-assertive [syn: {bumptious}]