The Collaborative International Dictionary of English v.0.48:

Decamp \De*camp"\, v. i. [imp. & p. p. Decamped (?; 215); p.
   pr. & vb. n. Decamping.] [F. d['e]camper; pref. d['e]- (L.
   dis) + camp camp. See Camp.]
   1. To break up a camp; to move away from a camping ground,
      usually by night or secretly. --Macaulay.
      [1913 Webster]

   2. Hence, to depart suddenly; to run away; -- generally used
      disparagingly.
      [1913 Webster]

            The fathers were ordered to decamp, and the house
            was once again converted into a tavern. --Goldsmith.
      [1913 Webster]

WordNet (r) 3.0 (2006):

decamp
    v 1: leave a camp; "The hikers decamped before dawn" [syn:
         decamp, break camp]
    2: run away; usually includes taking something or somebody
       along; "The thief made off with our silver"; "the accountant
       absconded with the cash from the safe" [syn: abscond,
       bolt, absquatulate, decamp, run off, go off, make
       off]
    3: leave suddenly; "She persuaded him to decamp"; "skip town"
       [syn: decamp, skip, vamoose]