They pick up what's said about fifty aristocrats (5)
I believe the answer is:
earls
'aristocrats' is the definition.
(earl is a kind of aristocrat)
'they pick up what's said about fifty' is the wordplay.
I cannot really understand how this works, but
'about' could be 'a' (abbreviation in Chambers) and 'a' is found within the answer.
'fifty' could be 'l' (Roman numeral) and 'l' is present in the answer.
The remaining letters 'ers' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for earls that I've seen before include "Laser the British peers" , "Nobles" , "London exhibition centre" , "Lear's out for the flight of the nobility" , "Noblemen (with a Court?)" .)