(1):
(v. i.) To use threats, or menaces; also, to have a threatening appearance.
(2):
(v. t.) To utter threats against; to menace; to inspire with apprehension; to alarm, or attempt to alarm, as with the promise of something evil or disagreeable; to warn.
(3):
(v. t.) To exhibit the appearance of (something evil or unpleasant) as approaching; to indicate as impending; to announce the conditional infliction of; as, to threaten war; to threaten death.