NOUN (4)

1. a student who crams;

2. a teacher who is paid to cram students for examinations;

3. a special school where students are crammed;

4. a textbook designed for cramming;

The Collaborative International Dictionary of English v.0.48:

Crammer \Cram"mer\ (kr[a^]m"m[~e]r), n.
   One who crams; esp., one who prepares a pupil hastily for an
   examination, or a pupil who is thus prepared. --Dickens.
   [1913 Webster] Cramoisie

WordNet (r) 3.0 (2006):

crammer
    n 1: a student who crams
    2: a teacher who is paid to cram students for examinations
    3: a special school where students are crammed
    4: a textbook designed for cramming