The Collaborative International Dictionary of English v.0.48:

Semantic \Sem*an"tic\, Semantical \Sem*an"tic*al\, n. sing. or
   pl. [Gr. shmantikos having meaning, from sh^ma a sign.]
   1. pertaining to the meanings of words.
      [PJC]

   2. of or pertaining to semantics.
      [PJC]

WordNet (r) 3.0 (2006):

semantic
    adj 1: of or relating to meaning or the study of meaning;
           "semantic analysis"

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "semantic":
   connotative, demonstrative, denominative, denotative, descriptive,
   designative, diagnostic, emblematic, evidential, exhibitive,
   expressive, figural, figurative, glossematic, glottochronological,
   grammatic, graphemic, iconic, identifying, ideographic,
   idiosyncratic, implicative, indicating, indicative, indicatory,
   individual, lexemic, lexical, lexicographic, lexicological,
   lexicostatistical, lingual, linguistic, meaningful, metalinguistic,
   metaphorical, morphemic, morphological, morphophonemic, naming,
   pathognomonic, peculiar, philological, phonemic, phonetic,
   phonological, phrasal, psycholinguistic, representative,
   semantological, semasiological, sememic, semiotic, signalizing,
   significant, significative, signifying, structural, suggestive,
   symbolic, symbolistic, symbological, symptomatic, symptomatologic,
   syntactic, typical, verbal