Put down in one's very best writing? (6)
I believe the answer is:
record
'put down' is the definition.
(I know that put down can be written as record)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for record that I've seen before include "Statement of events - best so far!" , "release" , "Make a single" , "Witness" , "Highest achievement" .)