Quivering wings of tender bird briefly infested with lice (9)
I believe the answer is:
tremulous
'quivering' is the definition.
(synonyms)
'wings of tender bird briefly infested with lice' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is found in the answer.
'bird' could be 'emu' (emu is a type of bird) and 'emu' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tremulous that I've seen before include "Quavering" , "Slightly shaking" , "Timid; quivering" , "Shaking, quivering" , "Timid; shaking" .)