To have very attractive features (usually the face) accentuated by "librarian-esque " glasses. Women who are sexy librarians don't have to work at libraries but they, at times, tend to be shy about their looks thereby adding to the "sexylibrarian" stature.
Alonso : Dude, Lisa's a Sexy Librarian because she gots a fine face, body and those glasses. But she denies it.
Jose: Yeah man she sure is. Can you believe she actually used to work at a Library?? I'd squank her. Just thinking of her makes me need a shanky.
A girl who's the best catch around. Sexy, gorgeous, smart. A renaissance girl who is wanted by every guy.
Damn, Sharon sure is a Sexy Librarian.