United supporters turning up in a bad way (5)
I believe the answer is:
snafu
'in a bad way' is the definition.
(snafu can mean chaotic)
'united supporters turning up' is the wordplay.
'united' becomes 'u'.
'supporters' becomes 'fans' (fan is a kind of supporter).
'turning up' is a reversal indicator.
'u'+'fans'='ufans'
'ufans' reversed gives 'SNAFU'.
(Other definitions for snafu that I've seen before include "in a bad state" , "a mess of things" , "Mess table" , "Chaotic state, mess" , "Chaotic situation" .)