A threat agent

mid-14c., aduersere, from Anglo-French adverser (13c.), Old French adversaire "adversary, opponent, enemy," or directly from Latin adversarius "opponent, adversary, rival," noun us [..]

An opponent. The defendant is the plaintiff's adversary.

Adversary [B](Heb. satan), an opponent or foe ( 1 Kings 5:4 ; 1 Kings 11:14 1 Kings 11:23 1 Kings 11:25 ; Luke 13:17 ); one that speaks against another, a complainant ( Matthew 5:25 ; Luke 12:58 ); an [..]

opponent or enemy.

someone who offers opposition Ad·ver·sary is an industrial project fronted by Jairus Khan, hailing from Ottawa, Canada. The Adversary is a fictional character, a demonic supervillain in [..]

(Heb. satan), an opponent or foe (1 Kings 5:4; 11:14, 23, 25; Luke 13:17); one that speaks against another, a complainant (Matt. 5:25; Luke 12:58); an enemy (Luke 18:3), and specially the devil (1 Pet [..]

To dream that you meet or engage with an adversary, denotes that you will promptly defend any attacks on your interest. Sickness may also threaten you after this dream. If you overcome an adversary, you will escape the effect of some serious disaster. See Enemies.   

one that contends with or opposes another ;esp : any of the opposing parties in a legal action

(n) someone who offers opposition

An adversary is a malicious entity whose aim is to prevent the users of the computer system from achieving data privacy, system integrity and availability. Actual adversaries are known as attackers

The opponent in a case or the other party

The system of dispute resolution used in countries evolved from the British legal system. The parties to the dispute are adversaries and each side does their best to prove their case and the court dec [..]

Any individual, group, organization, or government that conducts activities, or has the intention and capability to conduct activities, detrimental to critical assets.

An opponent or rival.

(religion,christianity) The Devil; Satan. * '''1998''', Daniel Isaac Block, ''The Book of Ezekiel: Chapters 25-48'', *: Yahweh?s turning Gog around, putting hooks in his jaws, and bringing him out [..]