Peggy Lee's signature song (5)
I believe the answer is:
fever
'peggy lee's signature song' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fever that I've seen before include "State of high excitement" , "(Illness causing) high temperature" , "A rise in the temperature from infection" , "Early part of flu" , "Intense nervous excitement or anticipation?" .)