The Collaborative International Dictionary of English v.0.48:
Preexistent \Pre`["e]x*ist"ent\, a. Existing previously; preceding existence; as, a pre["e]xistent state. --Pope. [1913 Webster]WordNet (r) 3.0 (2006):
pre-existent adj 1: existing previously or before something; "variations on pre-existent musical themes" [syn: preexistent, pre- existent, preexisting, pre-existing]