Stagger out to lunch in wrong direction (4)

I believe the answer is:

stun

I'm a little stuck... Click here to teach me more about this clue!

'stagger' is the definition.
(both can mean to shock)

'to lunch in wrong direction' is the wordplay.
'to lunch in wrong' becomes 'stu' (I can't explain this - if you can you should give a lot more credence to this answer).
'direction' becomes 'N' (compass direction north).
'stu'+'n'='STUN'

'out' is the link.

Can you help me to learn more?

(Other definitions for stun that I've seen before include "Daze, overwhelm" , "Knock cold" , "Bowl over" , "Numb with nuts" , "Render insensitive" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.