Synonyms for Fibrous (same or very similar meaning)
WordNet sense 1 (having or resembling fibers especially fibers used in making cordage such as those of jute):
hempenWordNet sense 2 ((of meat) full of sinews; especially impossible to chew):
sinewy, stringy, unchewableWordNet sense 3 (resistant to cutting or chewing):
toughFrom the ODE community, based on WordNetadd/edit