WordNet sense 1 ((of meat) full of sinews; especially impossible to chew):

fibrous, sinewy, unchewable

WordNet sense 2 (resistant to cutting or chewing):

tough

WordNet sense 3 (forming viscous or glutinous threads):

thready, ropey, ropy

WordNet sense 4 (relatively dense in consistency):

thick

WordNet sense 5 (lean and sinewy):

wiry

WordNet sense 6 (lacking excess flesh):

lean, thin

WordNet sense 7 (lacking material form or substance; unreal):

insubstantial, unreal, unsubstantial