During shift, say, letter finally resent (8)
I believe the answer is:
begrudge
'resent' is the definition.
(synonyms)
'during shift say letter finally' is the wordplay.
'during' means one lot of letters goes inside another.
'shift' becomes 'budge' (synonyms).
'say' becomes 'eg' (both can mean 'for example').
'finally' says to take the final letters.
The final letter of 'letter' is 'r'.
'eg'+'r'='egr'
'budge' placed around 'egr' is 'BEGRUDGE'.
(Other definitions for begrudge that I've seen before include "Envy the pleasure of" , "Unwillingly allow" , "Envy another's possessions or good fortune" , "Feel resentment and envy" , "Envy (someone) the enjoyment of" .)