Misspelling of the word "hot". Used predominantly by retarded teenagers when they are typing the word out. It is assumed that they add an extra t to give extra emphasis to the word, but they end up sounding illiterate and uneducated.
One that is so Hot that when described they are deserving of two "t's" rather than just one. Most commonly used by guys to describe an especially attractive lady. It is used just as much by the ladies but when complimented in this way, they take offense becuase most find it shallow.