involvement

be involved in, be engaged, enter the picture

important, significant

importance, consequence, significance

policy

decision / choice

to decide / to decide on; to choose

(politics) a government minister of Japan or ancient China

(historical) a major retainer / (historical) Same as だいじん (daijin) above

(politics, historical) a chief consul in the ancient Yamato court, equivalent to and replaced by 左大臣 (sadaijin) and 右大臣 (udaijin) during the Taika Reforms