Enquire after barrier material (6)
I believe the answer is:
damask
'material' is the definition.
(damask is a kind of material)
'enquire after barrier' is the wordplay.
'enquire' becomes 'ask' ('ask' can be a synonym of 'enquire').
'after' says to put letters next to each other.
'barrier' becomes 'dam' (dam is a kind of barrier).
'ask' put after 'dam' is 'DAMASK'.
(Other definitions for damask that I've seen before include "Patterned material" , "Silk or linen material woven with pattern on either side" , "Material, originally Syrian" , "Heavy embroidered linen" , "Table linen material" .)