Name a magician's move something incendiary (6)
I believe the answer is:
napalm
'something incendiary' is the definition.
(incendiary chemical)
'name a magician's move' is the wordplay.
'name' becomes 'n' (common abbreviation e.g. on forms).
'magician's move' becomes 'palm' (palm can mean to hide in your palm).
'n'+'a'+'palm'='NAPALM'
(Other definitions for napalm that I've seen before include "Does Ma plan to use the sticky jelly in fire bombs?" , "Petrol jelly used in flame-throwers" , "Petroleum jelly used in bombs and flame-throwers" , "Incendiary substance" , "Flammable jelly used in weapons" .)