Listen very carefully to Remain (4,2)
I believe the answer is:
hang on
'listen' is the definition.
Although both the answer and definition are verbs in their base form, I can't see how one could define the other.
'carefully to remain' is the wordplay.
'carefully' becomes 'on' (I can't justify this - if you can you should believe this answer much more).
'to' says to put letters next to each other (I've seen this in other clues).
'remain' becomes 'hang' (as in to hang around).
'on' after 'hang' is 'HANG ON'.
'very' acts as a link.
Can you help me to learn more?
(Other definitions for hang on that I've seen before include "Don't let go - just a mo'" , "Attend closely to - just a mo' (4,2)" , "Wait a mo', or hold tightly in suspense" , "Hold tight; wait" , "Hold the line" .)