"Works for me" (4)
(Other definitions for sure that I've seen before include "The old sewer" , "Completely certain" , "of course" , "Completely confident that one is right" , "Agreed" .)
(Other definitions for cool that I've seen before include "Hip - not warm" , "Chilled" , "Casual and confident - not heated" , "Unemotional or trendy" , "Moderately cold" .)
'works for me' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for yes that I've seen before include "Indeed" , "One response to "will you marry me?"" , "Positive response" , "Positive reply" , "Of course" .)