Stay on edge (6)
I believe the answer is:
reside
'stay' is the definition.
(thesaurus)
'on edge' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'edge' becomes 'side' (I've seen this before**).
're'+'side'='RESIDE'
(Other definitions for reside that I've seen before include "Desire (anag) - to live" , "Dwell permanently" , "Stay - desire (anag)" , "Make one's home permanently" , "Live in permanently" .)