Companion well informed about fashionable porcelain (9)
I believe the answer is:
chinaware
'porcelain' is the definition.
(I've seen this before)
'companion well informed about fashionable' is the wordplay.
'companion' becomes 'ch' (Companion of Honour).
'well informed' becomes 'aware' (I've seen this in another clue).
'about' means one lot of letters go next to another.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'aware' put after 'in' is 'inaware'.
'ch'+'inaware'='CHINAWARE'
(Other definitions for chinaware that I've seen before include "Ceramic articles" , "Fragile articles" , "service, perhaps" , "Dishes etc" , "Ceramics" .)