[n] a series of actions advancing a principle or tending toward a particular end; "he supported populist campaigns"; "they worked in the cause of world peace"; "the team was ready for a drive toward the pennant"; "the movement to end slavery"; "contributed to the war effort"
[n] any of the more or less continuous military expeditions in the 11-13th centuries when Christian powers of Europe tried to recapture the Holy Land from the Muslims
[v] go on a crusade; fight a holy war
[v] exert oneself continuously, vigorously, or obtrusively to gain an end or engage in a crusade for a certain cause or person; be an advocate for; "The liberal party pushed for reforms"; "She is crusading for women's rights"; "The Dean is pushing for his favorite candidate"