Some remarkably rich words for a song (5)
I believe the answer is:
lyric
'a song' is the definition.
(thesaurus)
'some remarkably rich words' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'LYRIC' can be found hidden inside 'remarkably rich words'.
'for' is the link.
(Other definitions for lyric that I've seen before include "Poem - verse - London theatre" , "Song's text" , "part of song" , "something to sing about? On the contrary" , "having a light quality" .)