Don't mention it! (3,2,3)
'don't mention it' is the definition.
(both can mean 'you're welcome')
This is the entire clue.
(Other definitions for not at all that I've seen before include "Don't mention it!" , "By no means - polite disclaimer" , "Anything but!" , "You're welcome" , "forget it" .)
(Another definition for sore spot that I've seen is " Touchy subject: bruise, perhaps".)
'don't mention it' is the definition.
(phrases used when someone thanks you for something)
This is the entire clue.
(Other definitions for no problem that I've seen before include "fine" , "Easy peasy!" , "Don't worry about it!" , "of course" .)
(Other definitions for taboo that I've seen before include "Forbidden by social custom" , "Prohibited by religion or custom" , "Subject to prohibition" , "(Irrational) prohibition" , "unacceptable" .)
'don't mention it' is the definition.
(I've seen this in another clue)
This is the entire clue.