1) Difficult to chew 2) Gristly 3) Of or relating to cartilage 4) Rubbery 5) Tough 1) Gristly 
hard and tough; gristly.
hard and tough in texture yet pliable
• (a.) Of or pertaining to cartilage; gristly; firm and tough like cartilage. • (a.) Having the skeleton in the state of cartilage, the bones containing little or no calcareous matter; said of certain fishes, as the sturgeon and the sharks.
<pathology> Composed of cartilage, a connective tissue substance that is present in joints. ... (27 Sep 1997) ... 
(kahr″tĭ-laj´ĭ-nәs) consisting of or of the nature of cartilage.
Firm but flexible, like cartilage in texture.
Car`ti·lag'i·nous adjective [ Latin cartilaginosus : confer French cartilagineux .] 1. Of or pertaining to cartilage; gristly; firm and tough like cartilage. 2. (Zoology) Having the skeleton in the state of cartilage, the bones containing little or no calcareous m...
Hard and tough, like parchment.
Type: Term Pronunciation: kar′ti-laj′i-nŭs Definitions: 1. Relating to or consisting of cartilage. Synonyms: chondral
hard and tough in texture yet pliable
(L: cartilago cartilege) made of cartilage. Cartilaginous fishes are the sharks and rays. Cartilage or gristle is a tough protein material found in higher animals and in which hard material is deposited to form bone. Young fish have cartilaginous bones that later harden.
[adj] - difficult to chew
gristly adjective difficult to chew