Old king is tender, as some might say (4)
I believe the answer is:
offa
'old king' is the definition.
(King of Mercia)
'tender as some might say' is the wordplay.
'tender as' becomes 'off' (I can't explain this - if you can you should give a lot more credence to this answer).
'some' means to look at the middle letters.
'might say' becomes 'abstraction' (might is a kind of abstraction).
The centre of 'abstraction' is 'a'.
'off'+'a'='OFFA'
'is' is the link.
Can you help me to learn more?
(Other definitions for offa that I've seen before include "Mercian leader" , "man throwing up defence" , "Mercia's dyke builder" , "Old Mercia king" , "King of Mercia, who may have built a dyke" .)