Clear, loud and always rising (4)
I believe the answer is:
free
'clear' is the definition.
(similar in meaning)
'loud and always rising' is the wordplay.
'loud' becomes 'f' (short for forte - 'loud' in music).
'and' says to put letters next to each other.
'always' becomes 'eer' (poetic way of saying ever).
'rising' is a reversal indicator (going up in a down clue).
'eer' in reverse letter order is 'ree'.
'f'+'ree'='FREE'
(Other definitions for free that I've seen before include "Reef (anag.)" , "Complimentary" , "Sewn-on trimming" , "Out of bondage" , "Allowed to do as one pleases" .)