Leader of Oman consumed by jealousy for deputy (5)
I believe the answer is:
envoy
'deputy' is the definition.
(thesaurus)
'leader of oman consumed by jealousy' is the wordplay.
'leader of' indicates taking the first letters.
'consumed by' is an insertion indicator (inserted letters get consumed).
'jealousy' becomes 'envy' (jealousy is an envious feeling).
The first letter of 'oman' is 'o'.
'o' put into 'envy' is 'ENVOY'.
'for' is the link.
(Other definitions for envoy that I've seen before include "One sent on a mission" , "Legate" , "Diplomatic representative" , "Emissary" , "Plenipotentiary" .)