Synonyms for Attrition (same or very similar meaning)
WordNet sense 1 (erosion by friction):
abrasion, corrasion, detrition
WordNet sense 2 (the wearing down of rock particles by friction due to water or wind or ice):
grinding
WordNet sense 3 (sorrow for sin arising from fear of damnation):
contriteness, contrition
From the ODE community, based on WordNet
add/edit