Sloot is the basic word. The more O's in "sloot", the sluttier the girl is. 2 O's is the minimum, you can add as many O's as necessary to add emphasis to just how slutty the girl is.
That bitch? Her and her friends are some slooooooooots, let me tell you.
There were some slooooooty girls at the party!
Prices shown in USD.