Resent deputy deficient in nothing (4)
I believe the answer is:
envy
'resent' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for envy that I've seen before include "grudging discontent" , "Spiteful resentment" , "Be green" , "Feeling of grudging admiration" , "Desire of another's property etc" .)