Source : Webster's Revised Unabridged Dictionary (1913)

Durative \Dur"a*tive\, a.
   Continuing; not completed; implying duration.

         Its durative tense, which expresses the thought of it
         as going on.                             --J. Byrne.

Source : WordNet®

durative
     n : the aspect of a verb that expresses its duration [syn: {durative
         aspect}]