Astonished by cockney's articulated equine trailer (3-6)
I believe the answer is:
awe-struck
'astonished' is the definition.
(awe-struck means astonished or amazed)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for awe-struck that I've seen before include "Lost for words" , "Filled with reverential fear" , "Showing a feeling of wonder and dread" , "Most impressed" , "Overcome by wonder" .)