(polite) first-person singular pronoun: I, me

a personal or private matter / (by extension) selfishness

personal, private / secret

a personal or private matter / selfishness / privacy, secrecy / (women's speech, obsolete) a brother-in-law

private; mine

(formal) first-person singular pronoun: I, me

as hard as one can; to the best of one's ability

self-realization

work done for free, unpaid work, uncompensated work / work done in vain, work with no favorable end result

to work for free, to work without pay or other compensation / to work in vain, to work with no favorable end result