Playing clarion before break of dawn is hard (8)
I believe the answer is:
ironclad
'is hard' is the definition.
(thesaurus)
'playing clarion before break of dawn' is the wordplay.
'playing' indicates anagramming the letters.
'before' means one lot of letters go next to another.
'break of dawn' becomes 'd' (I can't explain this - if you can you should give a lot more credence to this answer).
'clarion' anagrammed gives 'ironcla'.
'ironcla'+'d'='IRONCLAD'
Can you help me to learn more?
(Other definitions for ironclad that I've seen before include "well-protected" , "monitor, for example" , "Vessel well protected" , "Protected warship" , "Unassailable" .)