Figure unruly mob must be in mad rush (7)
I believe the answer is:
rhombus
'figure' is the definition.
(I know that rhombus is a type of parallelogram)
'unruly mob must be in mad rush' is the wordplay.
'unruly' indicates anagramming the letters.
'must be in' is an insertion indicator.
'mad' indicates anagramming the letters.
'mob' anagrammed gives 'omb'.
'rush' anagrammed gives 'rhus'.
'omb' put inside 'rhus' is 'RHOMBUS'.
(Other definitions for rhombus that I've seen before include "Equilateral 3" , "Diamond shape" , "Equilateral quadrilateral" , "Geometrical figure" , "Skewed square" .)