Jumper and anorak go in a jumble (8)
I believe the answer is:
kangaroo
'jumper' is the definition.
(thesaurus)
'anorak go in a jumble' is the wordplay.
'in a jumble' indicates an anagram.
'anorak'+'go'='anorakgo'
'anorakgo' anagrammed gives 'KANGAROO'.
'and' acts as a link.
(Other definitions for kangaroo that I've seen before include "Jumping animal" , "Large leaping mammal" , "Marsupial (both parts 4's friends)" , "Antipodean marsupial" , "Marsupial that boxes" .)