Relishing a bite after end of fast (7)
I believe the answer is:
tasting
'relishing' is the definition.
(synonyms)
'a bite after end of fast' is the wordplay.
'bite' becomes 'sting' (synonyms).
'after' says to put letters next to each other.
'end of' indicates one should take the final letters.
The last letter of 'fast' is 't'.
'a'+'sting'='asting'
'asting' after 't' is 'TASTING'.
(Other definitions for tasting that I've seen before include "Sampling (food)" , "event with wine" , "Savouring" .)