Fellow gave assistance after one dropped out tired (5)
I believe the answer is:
faded
'tired' is the definition.
(thesaurus)
'fellow gave assistance after one' is the wordplay.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'gave assistance' becomes 'ded' (I can't justify this - if you can you should give a lot more credence to this answer).
'after' means one lot of letters go next to another.
'one' becomes 'a'.
'ded' after 'a' is 'aded'.
'f'+'aded'='FADED'
'dropped out' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
(Other definitions for faded that I've seen before include "Bleached or deteriorated" , "Gradually disappeared" , "Washed out" , "Lost freshness or brilliance" , "Lost youth" .)