"complicated," 1640s, past-participle adjective from involve. Earlier it meant "spirally curved" (1610s).
Entries linking to involved
involve v.
late 14c., "envelop, surround; make cloudy or obscure," from Old French involver and directly from Latin involvere "envelop, surround, overwhelm," literally "roll into," from in- "in" (from PIE root *en "in") + volvere "to roll," from PIE root *wel- (3) "to turn, revolve." Mid-15c. as "concern oneself." Sense of "take in, include" first recorded c. 1600. Related: Involved; Involving.
Obscurest night involved the sky,
The Atlantic billows roared,
[Cowper, "The Castaway"]
self-involved adj.
"wrapped up in oneself or one's thoughts," 1812, from self- + involved.