Choir resolved to keep quiet concerning legendary musician (6)
I believe the answer is:
orphic
'choir resolved to keep quiet concerning legendary musician' is the definition.
I can't tell whether this defines the answer.
'choir resolved to keep quiet' is the wordplay.
'resolved' indicates anagramming the letters.
'to keep' means one lot of letters goes inside another.
'quiet' becomes 'p' (music symbol for 'piano').
'choir' is an anagram of 'orhic'.
'orhic' enclosing 'p' is 'ORPHIC'.
Can you help me to learn more?
(Other definitions for orphic that I've seen before include "Relating to legendary Greek lyre player" , "according to a great musician" , "Relating to a legendary lyre-player" , "Relating to Orpheus" , "Esoteric" .)