Knocked sideways at receiving an Irish farewell (6)
I believe the answer is:
aslant
'farewell' is the definition.
Both the definition and answer are adjectives. Maybe you can see a link between them that I can't see?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for aslant that I've seen before include "sloping away?" , "Athwart" , "crooked" , "on a slope" , "Leaning; out of plumb" .)