Lodge, small, by Scottish river (4)
I believe the answer is:
stay
'lodge' is the definition.
(I've seen this before)
'small by scottish river' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'by' says to put letters next to each other.
'scottish river' becomes 'tay' (I've seen this in another clue).
's'+'tay'='STAY'
(Other definitions for stay that I've seen before include "Supporting rope or wire" , "Corset strut" , "Guy rope" , "Remain; corset part" , "Board; continue" .)