Ms. Lofton is a minor character in Clarence, she is to be the principal at West Aberdale Elementary and is presumbably a rival of sorts to Ms. Shoop.
She has brown skin, dark brown hair and lips painted a dark red. She wears a pink T-shirt under a grey jacket and trousers of the same colour.
As you can see in "Field Trippin'" she is very strict with the students. If she sees someone inside his school, she will try to make him/her part of it, as seen in the same episode. She is Ms. Shoop's enemy, and from what we see, she has already taken several students from Aberdale Elementary.
The gallery for Ms. Lofton can be found here.