Boastfully

adv. [f. prec. + -LY².] In a boastful manner; vauntingly.

c. 1430.  Life St. Kath. (Gibbs MS.), 55. Wher yn bostfully she enhaunceth hir self.

1845.  Ld. Campbell, Chancellors (1857), III. li. 4. Observing boastfully, ‘We inherit all our genius from our mother.’