outbound vs departing

outbound and departing both are adjectives.

Word	Noun	Adjective	Verb	Adverb
outbound	No	Yes	No	No
departing	No	Yes	No	No

As adjectives, outbound and departing are synonyms defined as:

Other synonyms of outbound include outward-bound, outward.

outbound (adjective)	departing (adjective)
that is going out or leaving	that is going out or leaving