No, it's an adjective. Courteously is an adverb.
he asked her in courteous manner. Be courteous and you will get respect.
more courteous, most courteous
courteous
you are vey courteous
more courteous
The Ambassador is known to be courteous and gracious. Did the hotel clerk seem to be overly courteous?
courteous expression
The doorman was very courteous.
more interesting, most interesting more courteous, most courteous
He was very courteous by opening the door for me.
It is considered courteous for a man to stand when a woman arrives at his table. He pretended to be courteous, but he could not hide his dislike for the minister. Thank you for being so courteous.