1) Someone who you personally think is attractive, but other people don't necessarily agree.
2) A guy/girl who only you are attracted towards.
Dave: Dude, that girl is so hot.
Darren: Not at all man. What are you smoking? She's ugly.
Dave: We'll, I find her rather attractive.
Darren: Not to me. But I can see how you would be attracted to her.
Dave: She's DETRACTIVE.