false deity / tyrannical authority / transgressor
Masculine noun. From طَغَى (to transgress/rebel). Covers anything worshipped besides God, tyrannical rulers, and Satan. Plural: طَوَاغِيتُ (ṭawāghīt).
Rejecting ṭāghūt is a prerequisite for true faith in Islam - it means rejecting all false objects of worship and unjust authority.