Place hidden by grass lay empty by all accounts (9)
I believe the answer is:
reputedly
'place hidden by grass lay empty by all accounts' is the definition.
I can't tell whether this defines the answer.
'hidden by grass lay empty by all accounts' is the wordplay.
'hidden by' means one lot of letters goes inside another (inserted letters are hidden inside).
'grass' becomes 'reed' (type of grass plant).
'lay' becomes 'put' (both can mean to position or place something).
'empty by all accounts' becomes 'ly' (I can't explain this - if you can you should give a lot more credence to this answer).
'reed' placed around 'put' is 'reputed'.
'reputed'+'ly'='REPUTEDLY'
Can you help me to learn more?
(Other definitions for reputedly that I've seen before include "alleged" , "Allegedly" , "presumably" , "according to general belief" .)