Some upset by second prophet (5)
I believe the answer is:
moses
'prophet' is the definition.
(Moses is an example)
'some upset by second' is the wordplay.
'upset by' is an anagram indicator.
'second' becomes 's' (common abbreviation).
'some' anagrammed gives 'mose'.
'mose'+'s'='MOSES'
(Other definitions for moses that I've seen before include "One given tablets" , "Hebrew prophet who led the Israelites on the Exodus" , "Liberator" , "Great Jewish leader who led the flight from Egypt" , "He received the Ten Commandments on Mount Sinai" .)