Russian negative about outermost walls to hold your horses? (3,3)
I believe the answer is:
not yet
'hold your horses?' is the definition.
(I've seen this in another clue)
'russian negative about outermost walls' is the wordplay.
'russian negative' becomes 'nyet' (I've seen this in another clue).
'about' means one lot of letters goes inside another.
'walls' means to remove the middle letters (the walls are the letters on each edge).
'outermost' with its centre taken out is 'ot'.
'nyet' enclosing 'ot' is 'NOT YET'.
'to' is the link.
(Other definitions for not yet that I've seen before include "... but later on?" , "eventually" .)