Synonyms for Spiny (same or very similar meaning)
WordNet sense 1 (having spines):
spinousWordNet sense 2 (having or covered with protective barbs or quills or spines or thorns or setae etc.):
barbed, barbellate, bristly, prickly, thorny, setaceous, briary, briery, bristled, burred, burry, setoseWordNet sense 3 ((used of plants and animals) furnished with bristles and thorns):
armedFrom the ODE community, based on WordNetadd/edit