Bras from Brussels Lace? Had no idea that was possible! (8)
I believe the answer is:
clueless
'bras from brussels lace? had no' is the definition.
I can't tell whether this defines the answer.
'idea that was possible' is the wordplay.
'idea' becomes 'clue' (I've seen this in another clue).
'that was possible' becomes 'less' (I am not sure about this - if you are sure you should believe this answer much more).
'clue'+'less'='CLUELESS'
Can you help me to learn more?
(Other definitions for clueless that I've seen before include "Knowing nothing" , "such a crossword can't be solved!" , "Totally uninformed about what's going on" , "With no idea" , "sort of crossword that nobody can solve?" .)