WordNet sense 1 (an occurrence of something):

case, instance, case

WordNet sense 2 (punishment intended as a warning to others):

lesson, deterrent example, object lesson

WordNet sense 3 (a representative form or pattern):

model

WordNet sense 4 (something to be imitated):

exemplar, good example

WordNet sense 5 (an item of information that is representative of a type):

illustration, representative

WordNet sense 6 (a task performed or problem solved in order to develop skill or understanding):

exercise