Dance turn Hal’s upset about (4)
I believe the answer is:
hula
'dance' is the definition.
(I have seen 'Hawaiian dance' mean 'hula' so perhaps 'dance' could also mean 'hula')
'turn hal's upset about' is the wordplay.
'turn' becomes 'u' (a 'U-turn' is a kind of turn).
'upset' is an anagram indicator.
'about' means one lot of letters goes inside another.
'hal' is an anagram of 'hla'.
'u' put inside 'hla' is 'HULA'.
(Other definitions for hula that I've seen before include "Hawaiian dance - kind of hoop" , "Hawaiian rain dance" , "Hip-swaying dance of Hawaii" , "Hoop spun around the body" .)