It doesn’t change form of fresh promo — simply goes around (8)
I believe the answer is:
isomorph
'it doesn't change form' is the definition.
The definition suggests a singular noun which matches the answer.
'of fresh promo simply goes around' is the wordplay.
'of' indicates a hidden word.
'goes around' shows that the letters should be reversed in order (I've seen 'going around' mean this).
'hpromosi' can be found hidden inside 'fresh promo simply'.
'hpromosi' back-to-front is 'ISOMORPH'.
Can you help me to learn more?
(Other definitions for isomorph that I've seen before include "one exhibiting corespondence" , "unchanged in shape" .)