Quaver from end of anthem held by singer (7)
I believe the answer is:
tremble
'quaver' is the definition.
(thesaurus)
'end of anthem held by singer' is the wordplay.
'end of anthem' becomes 'm' (I can't justify this - if you can you should give a lot more credence to this answer).
'held by' means one lot of letters goes inside another.
'singer' becomes 'treble' (I've seen this before).
'm' going inside 'treble' is 'TREMBLE'.
'from' acts as a link.
Can you help me to learn more?
(Other definitions for tremble that I've seen before include "Quake in one's shoes" , "Show fear" , "Shake with fear or excitement" , "quail" , "Shiver slightly as with cold" .)