WordNet sense 1 (a worker (especially in an office) hired on a temporary basis):

temp, temporary worker

WordNet sense 2 (not eternal):

temporal

WordNet sense 3 (serving during an intermediate interval of time):

interim

WordNet sense 4 (tending to vanish like vapor):

evanescent

WordNet sense 5 (lasting a very short time):

ephemeral, passing, short-lived, transient

WordNet sense 6 (serving temporarily especially as a substitute):

acting

WordNet sense 7 (not permanent; not lasting):

impermanent

WordNet sense 8 (lacking continuity or regularity):

irregular

WordNet sense 9 (involving less than the standard or customary time for an activity):

part-time