ace up one's sleeve

to do something in preparation for something else / to do something and leave it in a certain state

at; in / on; upon / by; beside / at the time of

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

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