Cover old ground with imp leaving Hampshire (6)
I believe the answer is:
rehash
'imp leaving hampshire' is the definition.
I can't tell whether this definition defines the answer.
'cover old ground with' is the wordplay.
'cover' means to remove the middle letters (I've seen 'covers of' mean this).
'old' becomes 'ripe' ('ripe' can be similar in meaning to 'old').
'ground with' becomes 'hash' (I am not sure about this - if you are sure you should believe this answer much more).
'ripe' with its middle removed is 're'.
're'+'hash'='REHASH'
Can you help me to learn more?
(Other definitions for rehash that I've seen before include "Rework old material" , "Present again with just the odd change" , "That's nothing really new" , "Old material, slightly reworked and used again" , "Put old material into new form without much change" .)