Around the end of tour driver becomes cross (6)
I believe the answer is:
crabby
'cross' is the definition.
('crabby' can be a synonym of 'cross')
'around the end of tour driver' is the wordplay.
'around' means one lot of letters goes inside another.
'the end of' indicates one should take the final letters.
'driver' becomes 'cabby' (cabby is a kind of driver).
The final letter of 'tour' is 'r'.
'r' put within 'cabby' is 'CRABBY'.
'becomes' is the link.
(Other definitions for crabby that I've seen before include "Sour-tempered like common crustacean" , "Bad-tempered, irritable" , "Bad-tempered like common crustacean" , "Ill-tempered" , "petulant" .)