The Collaborative International Dictionary of English v.0.48:
Ruthful \Ruth"ful\, a. Full of ruth; as: (a) Pitiful; tender. (b) Full of sorrow; woeful. (c) Causing sorrow. --Shak. -- Ruth"ful*ly, adv. [1913 Webster]WordNet (r) 3.0 (2006):
ruthful adj 1: feeling or expressing pain or sorrow for sins or offenses [syn: contrite, remorseful, rueful, ruthful]