from the Greek suko-phantes, “fig-blabbers.” The men of Athens passed a law forbidding the exportation of figs; the law was little more than a dead letter, but there were always found mean fellows who, for their own private ends, impeached those who violated it; hence sycophant came to signify first a government toady, and then a toady generally.
“I here use `sycophant' in its original sense, as a wretch who
flatters the prevailing party by informing against his neighbours,
under pretence that they are exporters of prohibited flgs.” —
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894