脅迫 （キョウハク） threat, menace, coercion, blackmail

脅威 （キョウイ） threat, menace

威脅 （イキョウ） threat, menace

脅かす （おびやかす） to intimidate, to frighten, to scare, to threaten (e.g. peace), to jeopardize, to endanger, to imperil

脅す （おどす） to threaten, to menace, to frighten (into doing)

脅かす （おどかす） to threaten, to menace, to intimidate, to startle, to frighten, to scare