a personal or private matter / (by extension) selfishness

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

personal, private / secret

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

Alternative spelling of 私達 (“we; us”)

private; mine

science / a field of study

to do an experiment

accuracy, exactness

necessity (quality or state of being necessary, unavoidable, or absolutely requisite)