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

The Collaborative International Dictionary of English v.0.48:

Impending \Im*pend"ing\, a.
   Hanging over; overhanging; suspended so as to menace;
   imminet; threatening.
   [1913 Webster]

         An impending brow.                       --Hawthorne.
   [1913 Webster]

         And nodding Ilion waits th' impending fall. --Pope.

   Syn: Imminent; threatening. See Imminent.
        [1913 Webster]

WordNet (r) 3.0 (2006):

impending
    adj 1: close in time; about to occur; "retribution is at hand";
           "some people believe the day of judgment is close at
           hand"; "in imminent danger"; "his impending retirement"
           [syn: at hand(p), close at hand(p), imminent,
           impendent, impending]