Legendary bell-ringer seemingly altered mood (9)
I believe the answer is:
quasimodo
'legendary bell-ringer' is the definition.
'quasimodo' can be an answer for 'bell-ringer' (I've seen this before). I'm not certain of the 'legendary' bit.
'seemingly altered mood' is the wordplay.
'seemingly' becomes 'quasi' (I've seen this before).
'altered' indicates an anagram.
'mood' is an anagram of 'modo'.
'quasi'+'modo'='QUASIMODO'
Can you help me to learn more?
(Other definitions for quasimodo that I've seen before include "Fictional hunchback" , "Notre Dame hunchback" , "crooked character" , "Victor Hugo character" , "Sunday after Easter" .)