Sycophant /ˈsikəfənt/ noun
Definition: A person who acts obedient or attentive to an excessive degree toward someone important to gain an advantage. A person who tries to win favor with wealthy or famous people by paying them flattering compliments.
Etymology: The first known use of Sycophant dates back to the 1530s. The word has roots in Greek, Latin, and French. In Ancient Greek, sykophantēs, which translates to “one who shows the fig.” Later, sykophantēs would be used to describe someone who is a slanderer.
In Latin sȳcophanta, held a similar meaning and was used to describe someone as a trickster. By the time the word made its way to the English language, it had come to mean flatterer.
In a Sentence
Since Jane is constantly sucking up to our first-period teacher, everyone considers her a sycophant.
Jason is a sycophant social climber who doesn’t care what kind of groveling he has to do, as long as it advances his social calendar.
The Prime Minister usually surrounds herself with kind, well-meaning individuals. But today, she’s working with Kelly, a desperate sycophant who will do or say almost anything to the PM if she thinks it will advance her political career.
Flatterer, Toady, Fawner
Sincere, Unservile, Genuine
Being Greek myself, I will never use “sycophant” in the way of your examples, because it is still and will be for ever used in the Greek language in the malicious way you stayed that it meant originally. A sycophant is someone who makes false accusations against a person in order to denigrate that person’s reputation, whether he himself gains or NOT from the false accusation or rumor he spreads.