The Collaborative International Dictionary of English v.0.48:

lexical \lex"ic*al\ (l[e^]ks"[i^]*kal), a.
   Of or pertaining to a lexicon, to lexicography, or words;
   according or conforming to a lexicon. -- Lex"ic*al*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lexical
    adj 1: of or relating to words; "lexical decision task"
    2: of or relating to dictionaries

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "lexical":
   conjugate, derivative, echoic, etymologic, glossematic, iconic,
   lexemic, lexicographic, lexicologic, lexigraphic, morphemic,
   onomastic, onomatologic, onomatopoeic, paronymic, paronymous,
   phrasal, semantic, semantological, semasiological, sememic,
   semiotic, symbolic, verbal