Basic team Ellen assembled (9)
I believe the answer is:
elemental
'basic' is the definition.
('elemental' can be a synonym of 'basic')
'team ellen assembled' is the wordplay.
'assembled' indicates anagramming the letters.
'team'+'ellen'='teamellen'
'teamellen' with letters rearranged gives 'ELEMENTAL'.
(Other definitions for elemental that I've seen before include "Of nature's powers" , "Pertaining to weather or to first principles" , "Nature spirit" , "Basic, rudimentary" , "Related to the powers of nature" .)