Queen broadly happy about origin of cool musical genre (4)
I believe the answer is:
rock
'cool musical genre' is the definition.
'rock' can be an answer for 'cool' (thesaurus). I am unsure of the 'musical genre' bit.
'queen broadly happy about origin of' is the wordplay.
'queen' becomes 'r' (r is abbreviation regina. e.g. in ER ).
'broadly happy' becomes 'ck' (I can't justify this - if you can you should give a lot more credence to this answer).
'about' is a charade indicator (letters next to each other).
'origin' suggests taking the first letters (I've seen 'origins' mean this).
The first letter of 'of' is 'o'.
'ck' put after 'o' is 'ock'.
'r'+'ock'='ROCK'
Can you help me to learn more?
(Other definitions for rock that I've seen before include "Pop; precious stone" , "Shake; boulder" , "to soothe baby" , "Seaside confectionery" , "Gently move; boulder" .)