Very surprised how one can be knocked (8)
I believe the answer is:
sideways
'very' is the definition.
Both the definition and answer are adjectives. Maybe you can see an association between them that I can't see?
I don't understand how the rest of the clue works.
(Other definitions for sideways that I've seen before include "Askance" , "Obliquley, crabwise" , "Crabwise, laterally" , "Movement of crab" , "Walk this way, if you're a crab" .)