Six feet regularly cut down a small amount (4)
I believe the answer is:
atom
'small amount' is the definition.
(I've seen this in another clue)
'six feet regularly cut down a' is the wordplay.
I cannot really see how this works, but
'a' is found in the answer.
The remaining letters 'tom' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for atom that I've seen before include "Bit of make-up" , "Tiny particle, causes mighty explosion" , "Nucleus surrounded" , "Small particle of matter" , "Scrap" .)