原因【げんいん】
cause, origin, source
要因【よういん】
main cause, primary factor
死因【しいん】
cause of death
因果【いんが】
cause and effect, causality, karma, fate, unfortunate, unlucky, ill-fated
主因【しゅいん】
primary cause, main factor
因縁【いんねん】
fate, destiny, connection, tie, bond, origin, pretext, justification, hetu and prataya (direct causes and indirect conditions, which underlie the actions of all things)
誘因【ゆういん】
contributing cause, exciting cause, incentive, motive
因習【いんしゅう】
convention, tired tradition, old custom