Did he prophesy nothing for Sam to get upset about? (4)
I believe the answer is:
amos
'did he prophesy nothing' is the definition.
The definition suggests a singular noun which matches the answer.
'for sam to get upset about?' is the wordplay.
'for' becomes 'o' (I am not sure about this - if you are sure you should believe this answer much more).
'to get upset' indicates anagramming the letters (I've seen 'getting upset' mean this).
'about?' is an insertion indicator.
'sam' is an anagram of 'ams'.
'o' placed inside 'ams' is 'AMOS'.
Can you help me to learn more?
(Other definitions for amos that I've seen before include "30th OT book" , "Biblical prophet and OT book" , "man" , "Old Testament prophet" , "Hebrew prophet" .)