Somewhat here, there, always immaterial (8)
I believe the answer is:
ethereal
'immaterial' is the definition.
(I've seen this in another clue)
'somewhat here there always' is the wordplay.
'somewhat' indicates a hidden word.
'ETHEREAL' is hidden in the letters of 'here there always'.
(Other definitions for ethereal that I've seen before include "Impalpable" , "'Fairy-like, delicate (8)'" , "Delicate and perfect" , "Delicate - airy" , "Airy or supernatural" .)