Source : Webster's Revised Unabridged Dictionary (1913)

Syncopate \Syn"co*pate\, v. t. [imp. & p. p. {Syncopated}; p.
   pr. & vb. n. {Syncopating}.] [LL. syncopatus, p. p. of
   syncopare to syncopate, to swoon. See {Syncope}.]
   1. (Gram.) To contract, as a word, by taking one or more
      letters or syllables from the middle; as, ``Gloster'' is a
      syncopated form of ``Gloucester.''

   2. (Mus.) To commence, as a tone, on an unaccented part of a
      measure, and continue it into the following accented part,
      so that the accent is driven back upon the weak part and
      the rhythm drags.

Source : WordNet®

syncopated
     adj : stressing a normally weak beat