Pause, welcoming coach's check (9)
I believe the answer is:
restraint
'check' is the definition.
(thesaurus)
'pause welcoming coach's' is the wordplay.
'pause' becomes 'rest' (rest is a kind of pause).
'welcoming' means one lot of letters goes inside another (in sense of 'inviting in').
'coach' becomes 'train' ('train' can be a synonym of 'coach').
'rest' placed around 'train' is 'RESTRAINT'.
(Other definitions for restraint that I've seen before include "controlling influence" , "Control, restriction, curtailment" , "Start rain as an impediment" , "Moderation" , "Something that holds back" .)