to leave (a person or thing) alone (also †one): to stop or abstain from interfering with or paying attention to; to let alone (see let, v.1 18b).

transitive. To refrain from enforcing, pressing, or demanding; not to urge, press, insist on, or exact. Sometimes with double object. Now rare. †Also…

to let fall. †To allow (one's anger) to abate (obsolete); to allow to lapse, proceed no further with, ‘drop’ (a business). ? Obsolete.

transitive. To refrain from pursuing, or be no longer able to pursue (a matter). Apparently only in to fall one's suit (cf. suit, n. 4). Obsolete.

transitive. To forbear persistence in (an action or course of action); to refrain from pressing (an objection, a scruple, an argument).

figurative. To refrain from proceeding with or prosecuting (a course of action, a proposal, etc.); to cease to support or present (a candidate, etc.).

to leave it at that: to proceed no further with a matter; to refrain from pressing a point.