Underworld traveller to express worn-out condition (9)
I believe the answer is:
disrepair
'worn-out condition' is the definition.
'disrepair' can be an answer for 'condition' (disrepair is a kind of condition). I'm not certain of the 'worn-out' bit.
'underworld traveller to express' is the wordplay.
'underworld' becomes 'dis' (underworld in classical mythology).
'traveller' becomes 'rep' (travel company worker).
'to express' becomes 'air' (I've seen this before).
'dis'+'rep'+'air'='DISREPAIR'
Can you help me to learn more?
(Other definitions for disrepair that I've seen before include "State of collapse" , "rack and ruin" , "In need of mending" , "broken-down state" , "Poor working order" .)