The Collaborative International Dictionary of English v.0.48:

Impend \Im*pend"\, v. t. [L. impend[e^]re; pref. im- in +
   pend[e^]re to weigh out, pay.]
   To pay. [Obs.] --Fabyan.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Impend \Im*pend"\, v. i. [imp. & p. p. Impended; p. pr. & vb.
   n. Impending.] [L. impend[=e]re; pref. im- in + pend[=e]re
   to hang. See Pendant.]
   To hang over; to be suspended above; to threaten from near at
   hand; to menace; to be imminent. See Imminent.
   [1913 Webster]

         Destruction sure o'er all your heads impends. --Pope.
   Impendence

WordNet (r) 3.0 (2006):

impend
    v 1: be imminent or about to happen; "Changes are impending"