A disastrous hairstyle normally due to a tragic trip to a hair salon. This could be due to lack of experience on the stylists' behalf or a customer insisting to have a certain cut but not being aware that it doesn't suite their appearance. A hairaster could be known to the individual (who will normally try to hide the said disaster) or the individual could be completely ignorant of the ensuing eyesore.
Other possible methods of obtaining a hairaster are: having a bad bad hair day, waking up late with no time to get ready, or a poor choice of "taking a risk."
Normally your friends won't even mention the extreme change in hair lifestyle, but will openly discuss it not in your presence. It is also mandatory of your friends to take pictures and send to other friends in order to both warn them and give them an opportunity to think of something whitty.
Hey Janie, did you get that picture of Annette's hair I sent you? OMG yes, total hairaster!!!