When there’s a panic, Alf turns quiet (4)
I believe the answer is:
flap
'when there's a panic' is the definition.
I can't judge whether this defines the answer.
'alf turns quiet' is the wordplay.
'turns' shows that the letters should be reversed in order.
'quiet' becomes 'p' (music symbol for 'piano').
'alf' in reverse letter order is 'fla'.
'fla'+'p'='FLAP'
Can you help me to learn more?
(Other definitions for flap that I've seen before include "Move wings - panic!" , "Minor panic; tab" , "Moving surface on wing" , "Move like a bird or get into a tizzy" , "Adjustable part of wing - panic" .)