He has to do something dramatic (5)
I believe the answer is:
actor
'he has to do something dramatic' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he has to do something' is the wordplay.
'he has' becomes 'or' (I can't explain this - if you can you should believe this answer much more).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'do something' becomes 'act' (I've seen this before).
'or' after 'act' is 'ACTOR'.
Can you help me to learn more?
(Other definitions for actor that I've seen before include "Gielgud, say" , "One taking part" , "eg Anthony Hopkins" , "Performer in drama" , "Dramatic artist" .)