Prosecutor

n. plaintiff, person who files a legal action; prosecuting attorney, attorney who manages the accusing side of a legal trial

The prosecutor is the chief legal representative of the prosecution in countries adopting the common law adversarial system or the civil law inquisitorial system. The prosecution is the legal party responsible for presenting the case against an individual suspected of breaking the law in a criminal trial.
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Noun
1. a government official who conducts criminal prosecutions on behalf of the state
(synonym) public prosecutor, prosecuting officer, prosecuting attorney
(hypernym) official, functionary
(hyponym) district attorney, DA
(derivation) prosecute
(classification) law, jurisprudence

n. prosecutor, plaintiff, person who files a legal action; prosecuting attorney, attorney who manages the accusing side of a legal trial

(n.)
The person who institutes and carries on a criminal suit against another in the name of the government.
  

(n.)
One who prosecutes or carries on any purpose, plan, or business.