Source : Webster's Revised Unabridged Dictionary (1913)

Outbound \Out"bound`\, a.
   Outward bound. --Dryden.

Source : WordNet®

outbound
     adj : that is going out or leaving; "the departing train"; "an
           outward journey"; "outward-bound ships" [syn: {departing(a)},
            {outward}, {outward-bound}]