The Collaborative International Dictionary of English v.0.48:

School-teacher \School"-teach`er\, n.
   One who teaches or instructs a school. --
   School"-teach`ing, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

schoolteacher
    n 1: a teacher in a school below the college level [syn:
         schoolteacher, school teacher]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "schoolteacher":
   abecedarian, certified teacher, docent, doctor, dominie, don,
   educationist, educator, fellow, guide, guru, instructor, maestro,
   master, melamed, mentor, mullah, pandit, pedagogist, pedagogue,
   preceptor, professor, pundit, rabbi, schoolkeeper, schoolmaster,
   schoolmistress, starets, teacher, tutor