Bluey's friend is out of condition (5)
I believe the answer is:
rusty
'out of condition' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for rusty that I've seen before include "Antiquated" , "Impaired through lack of use" , "showing sign of inactivity?" , "(Of iron) affected by damp" , "a bit faded" .)