Condition to run in (4)
I believe the answer is:
nick
This could be a double definition.
'condition' is the first definition.
(as in the phrase 'in good nick')
'run in' is the second definition.
'nick' can be an answer for 'run' (nick can mean to run quickly). I am not sure about the 'in' bit.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for nick that I've seen before include "Score - police station" , "Pinch, steal" , "Small cut - if old, the devil" , "Nab; notch" , "Small cut; steal" .)