Relative caught in fiasco US instigated (6)
I believe the answer is:
cousin
'relative' is the definition.
(I know that cousin is a type of relative)
'caught in fiasco us instigated' is the wordplay.
'caught in' indicates a hidden word.
'COUSIN' can be found hidden inside 'fiasco us instigated'.
(Other definitions for cousin that I've seen before include "Kinsman, generally (archaic)" , "person once removed?" , "one in my family" , "An uncle or aunt's child" , "An aunt's or uncle's child" .)