WordNet sense 1 (a justification for something existing or happening):

grounds, reason

WordNet sense 2 (give rise to; cause to happen or occur, not always intentionally):

do, make, do

WordNet sense 3 (a comprehensive term for any proceeding in a court of law whereby an individual seeks a legal remedy):

case, lawsuit, suit, causa, case

WordNet sense 4 (a series of actions advancing a principle or tending toward a particular end):

campaign, crusade, drive, effort, movement

WordNet sense 5 (cause to do; cause to act in a specified manner):

get, have, stimulate, induce, have

WordNet sense 6 (any entity that produces an effect or is responsible for events or results):

causal agent, causal agency