The Greek for sycophant is συκοφάντης (sykophántēs). It suggests someone who brings all kinds of charges and proves none, according to a client of Demosthenes. A client of Lysias adds the perspective of blackmail: "It is their practice to bring charges even against those who have done no wrong. For from these they would gain most profit."  In this context, the word entails false accusation, malicious prosecution, and abuse of legal process for mischievous or fraudulent purposes.
In ancient Greece the word was the Athenian counterpart of the Roman delator, a public informer. In modern Greek the term has retained its ancient classical meaning, and is still used to describe a slanderer or a calumniator.