Complex system in Saudi regularly defied understanding (6)
I believe the answer is:
amazed
'defied understanding' is the definition.
Although both the answer and definition are past participle verbs, I cannot see how they can define each other.
'complex system in saudi regularly' is the wordplay.
'complex system' becomes 'maze' (maze is a kind of system. I am not sure about the 'complex' bit.).
'in' means one lot of letters goes inside another.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternate letters of 'saudi' are 'ad'.
'maze' placed inside 'ad' is 'AMAZED'.
Can you help me to learn more?
(Other definitions for amazed that I've seen before include "knocked for six" , "Greatly surprised, never would have thought it" , "Awe-struck" , "Flabbergasted" , "Astonished, astounded" .)