Source : Webster's Revised Unabridged Dictionary (1913)

Pretentious \Pre*ten"tious\, a. [Cf. F. pr['e]tentieux. See
   {Pretend}.]
   Full of pretension; disposed to lay claim to more than is
   one's; presuming; assuming. -- {Pre*ten"tious*ly}, adv. --
   {Pre*ten"tious*ness}, n.

Source : WordNet®

pretentiously
     adv : in a pretentious manner; "this author writes pretentiously"
           [ant: {unpretentiously}]