Singer frequently getting half confused (4)
I believe the answer is:
alto
'singer' is the definition.
(alto is a kind of singer)
I cannot understand how the rest of the clue works.
(Other definitions for alto that I've seen before include "Second of four parts (in singing)" , "Low female singing voice" , "The highest adult male singing voice" , "Key old > male who scores high" , "Singing voice between tenor and soprano" .)