Stop or pass on (5)
I believe the answer is:
colon
'stop' is the definition.
(thesaurus)
'pass on' is the wordplay.
'pass' becomes 'col' (col is a term for a mountain pass).
'col'+'on'='COLON'
'or' is the link.
(Other definitions for colon that I've seen before include "Punctuation mark; gut" , "Panamanian port" , "Stop (less than full)" , "Part of the intestine - punctuation mark" , "Part of body; two dots" .)