The definition of a harlot according to scripture is a religious system who has no legitimate husband, but continues to influence worldly kings, governors and others, by promulgating that Jesus and the disciples were an occult group, that they labeled the Nazarene Sect. This action by the Jewish religious institution of those days would essentially reject the husband that was sent to gather her.
Listen to what Jesus said.......
37“Jerusalem, Jerusalem, you who kill the prophets and stone those sent to you, how often
I have longed to gather your children together, as a hen gathers her chicks under her wings, and you were not willing. 38Look, your house is left to you desolate. (Matthew 23:37-38)
Jesus as the husband who came to gather Jerusalem's children would finally decide to leave her, by saying look, your house is left to you desolate. This proclaiming by Jesus means that this religious establishment became a husbandless harlot.
Jesus was against the Jewish Church establishment and he would charge it with the murder of Abel, right through to the murder of Zechariah, who was the last Old Testament prophet. Though they had no hand in the murder of Abel, this means that Jesus denied the ligitamacy of this establishment from its beginnings, right until its end, when Jesus said your house I saw left to you desolate.
I am merely quoting Jesus and showing how he thought about this religious establishment.
John identifies who this harlot of Babylon is by the following statement.......
And their bodies will lie in the main street of
Jerusalem, the city that is figuratively called "Sodom" and "Egypt,"
the city where their Lord was crucified. (Revelation 11:8)