Roll up unadulterated joint and ignite (5)
I believe the answer is:
erupt
'ignite' is the definition.
(synonyms)
'roll up unadulterated joint' is the wordplay.
'roll up' shows that the letters should be reversed in order (I've seen 'rolling up' mean this).
'unadulterated' becomes 'pure' (similar in meaning).
'joint' becomes 't' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'pure' backwards is 'erup'.
'erup'+'t'='ERUPT'
'and' is the link.
Can you help me to learn more?
(Other definitions for erupt that I've seen before include "Blow up like volcano" , "Break forth" , "Burst forth violently" , "Discharge" , "Emit lava" .)