Tough fibrous tissue in the body (8)
I believe the answer is:
ligament
'tough fibrous tissue in the body' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ligament that I've seen before include "What may get torn" , "Fibrous tissue joining bones or cartilage" , "Band of tissue joining bones" , "Link between bones or cartilages" , "Joint connector" .)