The Collaborative International Dictionary of English v.0.48:

Liturgic \Li*tur"gic\, Liturgical \Li*tur"gic*al\, [Gr. ?: cf.
   F. liturgique.]
   Pertaining to, of or the nature of, a liturgy; of or
   pertaining to public prayer and worship. --T. Warton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

liturgical
    adj 1: of or relating to or in accord with liturgy

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "liturgical":
   High-Church, alto, baptismal, baritone, bass, bravura, ceremonial,
   ceremonious, choral, choric, coloratura, conventional, decorous,
   dramatic, eucharistic, falsetto, formal, formular, formulary,
   heroic, hieratic, hymnal, liturgic, liturgistic, lyric, operatic,
   paschal, pompous, psalmic, psalmodial, psalmodic, ritual,
   ritualistic, sacerdotal, sacramental, sacramentarian, sacred,
   singing, solemn, soprano, stately, tenor, treble, vocal,
   well-mannered