Swiss song (5)
I believe the answer is:
yodel
'swiss song' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for yodel that I've seen before include "Sing (Alpine folk music)" , "Sing in Tyrolean fashion" , "Falsetto singing" , "Sing like the Lonely Goatherd?" , "Sing using falsetto" .)