月末: the end of the month

(idiomatic) can't be undone, can't be saved, unable to recover

Alternative form of 取り返しがつかない

(informal, video games) to lag

A person whose name has become identified with a particular object or activity; eponym.

(literary) an alternate name

(computing) a filename

to give one’s name (as), to call oneself (name, etc.) / to impersonate or claim to be (someone)

a surname

a surname