What does "enclitic" mean?

Enclitic: Affixed; subjoined; -- said of a word or particle which leans back upon the preceding word so as to become a part of it, and to lose its own independent accent, generally varying also the accent of the preceding word.

Additional senses

  1. 2.A word which is joined to another so closely as to lose its proper accent, as the pronoun thee in prithee (pray thee).

Sources