Take case back - it retains value when retired (8)
I believe the answer is:
emeritus
'retired' is the definition.
(synonyms)
'take case back it retains value when' is the wordplay.
I cannot quite see how this works, but
'take' could be 'r' (abbreviation for 'recipe', Latin for 'take') and 'r' is present in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for emeritus that I've seen before include "Retired but retaining a courtesy title" , "No longer having old chair" , "Retiring academic" , "Keeping hon. title in retirement" , "Use remit for retained title of retired professional" .)