The Collaborative International Dictionary of English v.0.48:

Expeditious \Ex`pe*di"tious\, a.
   Possessed of, or characterized by, expedition, or efficiency
   and rapidity in action; performed with, or acting with,
   expedition; quick; having celerity; speedily; as, an
   expeditious march or messenger. -- Ex`pe*di"tious*ly, adv.
   -- Ex`pe*di"tious*ness, n.

   Syn: Prompt; ready; speedy; alert. See Prompt.
        [1913 Webster]

WordNet (r) 3.0 (2006):

expeditious
    adj 1: marked by speed and efficiency