"Don't worry about it" (2,5)
I believe the answer is:
no sweat
'don't worry about it' is the definition.
(phrase meaning there's nothing to worry about)
This is the entire clue.
(Other definitions for no sweat that I've seen before include "Not a problem! (informal)" , "That's a piece of cake (anti-perspirant unnecessary!)" , "Not a problem (US colloq.)" , "There shouldn't be any objection" , "That's not a problem!" .)