The Collaborative International Dictionary of English v.0.48:

Filial \Fil"ial\, a. [L. filialis, fr. filius son, filia
   daughter; akin to e. female, feminine. Cf. Fitz.]
   1. Of or pertaining to a son or daughter; becoming to a child
      in relation to his parents; as, filial obedience.
      [1913 Webster]

   2. Bearing the relation of a child.
      [1913 Webster]

            And thus the filial Godhead answering spoke.
                                                  --Milton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

filial
    adj 1: designating the generation or the sequence of generations
           following the parental generation [ant: parental]
    2: relating to or characteristic of or befitting an offspring;
       "filial respect" [ant: maternal, parental, paternal]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "filial":
   adoring, affectionate, conjugal, daughterlike, daughterly,
   demonstrative, devoted, faithful, fond, husbandly, languishing,
   lovelorn, lovesick, lovesome, loving, maternal, melting, parental,
   paternal, romantic, sentimental, soft, sonlike, sonly, tender,
   uxorious, wifely