Rent difficulty causing a storm (7)
I believe the answer is:
tornado
'storm' is the definition.
(type of weather)
'rent difficulty' is the wordplay.
'rent' becomes 'torn' (synonyms).
'difficulty' becomes 'ado' (ado is bother or difficulty).
'torn'+'ado'='TORNADO'
'causing a' is the link.
(Other definitions for tornado that I've seen before include "squall" , "RAF fighter; whirlwind" , "Severe wind" , "Typhoon" , "Cyclone, twister" .)