Source : Webster's Revised Unabridged Dictionary (1913)

Indefinitely \In*def"i*nite*ly\, adv.
   In an indefinite manner or degree; without any settled
   limitation; vaguely; not with certainty or exactness; as, to
   use a word indefinitely.

         If the world be indefinitely extended, that is, so far
         as no human intellect can fancy any bound of it. --Ray.

Source : WordNet®

indefinitely
     adv : to an indefinite extent; for an indefinite time; "this could
           go on indefinitely"