Sloth's middle toe is damaged and redundant (6)
I believe the answer is:
otiose
'redundant' is the definition.
(I've seen this before)
'sloth's middle toe is damaged' is the wordplay.
'middle' says to take the centre.
'damaged' indicates an anagram.
The central letter of 'sloth' is 'o'.
'toe'+'is'='toeis'
'toeis' with letters rearranged gives 'tiose'.
'o'+'tiose'='OTIOSE'
'and' is the link.
(Other definitions for otiose that I've seen before include "Slothful" , "Indolent, ineffectual" , "Indolent or superfluous" , "Serving no practical purpose" , "Devoid of worth or significance" .)