When it comes to beauty, every species has its own definitions, and what one species finds attractive may be the complete opposite of another. So someone, somewhere, might think you’re okay-looking, but no-one from your own species would agree with that assessment. You better hope to have a winning personality to make up for what you lack in the looks department.
Your unattractiveness affects how others react to you in a negative way; you suffer a 1D+0 penalty to Persuade, Lead, Con, and Perform when interacting with a species who does not find your repulsiveness conventionally attractive. On the upside, you gain a 0D+2 bonus to Intimidate, because you’re a hideous creature a mother might use to scare her children into going to bed on time.