Crab adjectives are listed in this post. Each word below can often be found in front of the noun crab in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing CRAB.
big, blue, common, dungeness
fresh, giant, green, hermit
horseshoe, large, little, live
lump, old, red, roasted
shell, shelled, siberian, small
spicy, tiny, wild
Hope this word list had the adjective used with crab you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.