Description of space left audience flabbergasted (9)
I believe the answer is:
euclidean
'description of space' is the definition.
'Euclidean' can be an answer for 'space' (Euclidean space is an example). I am not sure about the 'description of' bit.
'left audience flabbergasted' is the wordplay.
'left' becomes 'l' (common abbreviation).
'flabbergasted' is an anagram indicator (I've seen this in other clues).
'l'+'audience'='laudience'
'laudience' with letters rearranged gives 'EUCLIDEAN'.
Can you help me to learn more?
(Other definitions for euclidean that I've seen before include "type of geometry" , "Of an ancient system of geometry" , "of ancient Greek" , "kind of geometry" .)