Cabbie's first comfort stop (5)
I believe the answer is:
'stop' is the definition.
(I know that stop can be written as cease)
'cabbie's first comfort' is the wordplay.
'cabbie's first' becomes 'c' (1st letter of 'cabbie').
'comfort' becomes 'ease' (synonyms).
(Other definitions for cease that I've seen before include "Come to an end" , "Stop, give over" , "Political group" , "Finish, end" , "Desist" .)