Rock in great confusion (7)
I believe the answer is:
granite
'rock' is the definition.
(type of rock)
'in great confusion' is the wordplay.
'confusion' is an anagram indicator.
'in'+'great'='ingreat'
'ingreat' with letters rearranged gives 'GRANITE'.
(Other definitions for granite that I've seen before include "Hard stone from Tangier" , "Get rain (anag) - rock" , "Tangier (anag.)" , "Very hard type of rock" , "Tearing (anag.)" .)