The Collaborative International Dictionary of English v.0.48:

Philological \Phil`o*log"ic*al\, Philologic \Phil`o*log"ic\, a.
   [Cf. F. philologique.]
   Of or pertaining to philology. -- Phil`o*log"ic*al*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

philological
    adj 1: of or relating to or dealing with philology

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "philological":
   descriptive, glottochronological, grammatic, graphemic,
   lexicographic, lexicological, lexicostatistical, lingual,
   linguistic, metalinguistic, morphological, morphophonemic,
   phonemic, phonetic, phonological, psycholinguistic, semantic,
   structural, syntactic