A promiscuous female that tends to be attracted to bad male youths also known as road men. In this case, the 'op' is the male youth and the thot is the female. Not a good thing to be called.
A male to female transvestite, who has had all the alterations possible with the exception of removal/reversal of the penis and testicles. Pre-op Trannies often keep these male parts in order to maximize their opportunities in the sex-trade industry.
Many Pre-op Trannies turn to the sex trade, because they find it difficult to be accepted in mainstream society. She is a beautiful Pre-op Tranny, she's probably very successful in her trade.