Stagger back and stare (4)
I believe the answer is:
leer
'stare' is the definition.
The answer and definition can be both to do with perception as well as being verbs in their base form.
Maybe they are linked in a way I don't understand?
'stagger back' is the wordplay.
'stagger' becomes 'reel' (both can mean to move around without balance).
'back' is a reversal indicator.
'reel' reversed gives 'LEER'.
'and' is the link.
Can you help me to learn more?
(Other definitions for leer that I've seen before include "Stare suggestively" , "Give sly look" , "Suggestive or sneering grin" , "Ogle, smirk" , "Give lascivious look" .)