Old toiler who could never quite turn up fresh (4)

I believe the answer is:

serf

I'm a little stuck... Click here to teach me more about this clue!

'old toiler' is the definition.
'serf' can be an answer for 'toiler' (I've seen this in another clue). I'm not sure about the 'old' bit.

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for serf that I've seen before include "Old worker" , "Tied labourer" , "Servant, vassal" , "Feudal estate worker" , "Thrall" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.