A tendency to shut up and then sing out (8)
I believe the answer is:
penchant
'a tendency' is the definition.
(thesaurus)
'shut up and then sing out' is the wordplay.
'shut up' becomes 'pen' (pen can mean to shut in or enclose).
'and then' means one lot of letters go next to another (I've seen this in other clues).
'sing out' becomes 'chant' (chanting is a kind of singing. I am not sure about the 'out' bit.).
'pen'+'chant'='PENCHANT'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for penchant that I've seen before include "'Predilection, a strong liking (8)'" , "Inclination, bent" , "Fondness (for) - bias (towards)" , "Willingness" , "Inclination; taste" .)