Returning letter to Athens, attache died alone (7)
I believe the answer is:
unaided
'alone' is the definition.
(I've seen this in another clue)
'returning letter to athens attache died' is the wordplay.
I cannot really understand how this works, but
'letter' could be 'u' and 'u' is present in the answer.
an anagram of 'died' is 'ided' which is located in the answer.
The remaining letters 'na' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for unaided that I've seen before include "Without help or support" , "having received zero help" , "Dun aide being without help" , "Without extra help" , "Done by oneself alone" .)