expression, godan verb (-su)
do one's part; fulfill one's duty
Rare, formal expression meaning to carry out one's assigned role or responsibility. The phrase uses 己 (oneself) and 分 (one's lot/station), implying a sense of duty tied to one's position.
彼は常に己の分を尽くすことを心がけている。
He always strives to do his part.
Common modern expression for fulfilling one's role; 己の分を尽くす is a rare, literary equivalent with a more self-conscious, duty-bound nuance.
A set phrase combining 己 (oneself), 分 (one's lot, station, or duty), and 尽くす (to exhaust, to do fully). The exact origin is uncertain, but it reflects a traditional Japanese sense of duty to one's role.