Revelation 17:5
5 And on her forehead a name was written: MYSTERY, BABYLON THE GREAT, THE MOTHER OF HARLOTS...

Jeremiah 3:6
6 The LORD said also to me in the days of Josiah the king: "Have you seen what backsliding Israel has done? She has gone up on every high mountain and under every green tree, and there played the harlot.

Harlot = one who rather spend time with another person rather than their spouse.
Sinner = One who does not profess a following of Christ (even though they may believe) and rather pursue the pleasures, riches, and things of this world.
Christian = One who Follows the example of Christ, leaving behind riches and doing the will of God.
Harlot Christian = One who professes the following of Christ but forsakes the work of God to pursue the pleasures, riches, and this of this world.

1 John 2:15
15 Do not love the world or the things in the world. If anyone loves the world, the love of the Father is not in him.

Any question?