Lie next to
I believe the answer is:
abut
'lie next to' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for abut that I've seen before include "Adjoin, touch" , "Adjoin -- 19 (rev)" , "Lean against the odd tuba" , "Be next to -- share a boundary" , "Of building or land, end or lean against" .)