Demon

A demon is a supernatural being that is usually presented as being evil.

Once in 2366, Lwaxana Troi mispronounced the Ferengi title "DaiMon" as "demon". 

Upon meeting Data in 2370, Talur thought his grandmother would have believed the android to be a demon. 

In 2371 of an alternate timeline, Latika panicked after becoming convinced that Kathryn Janeway and Tom Paris, who had seemingly miraculously appeared on the boy's homeworld but had actually traveled there from the near future via subspace fractures, were demons that had appeared "out of thin air" but a cynical law enforcement officer dismissed the child's fears, telling the boy that he had been reading too many Darkstorm'' tales and that demons did not really exist, before instructing the boy to move along. After Latika later approached the visitors with accusations that they were lying, an irritated Paris pretended to confirm the child's fears and claimed that both he and Janeway ate young boys, scaring Latika away. He never again repeated his claims that the two visitors were demons and soon discovered their true identities, ultimately becoming friends with Paris.''

As the two adversaries met for the last time in the Fire Caves in 2375, Dukat called himself a demon and Benjamin Sisko an angel.