Harsh to exclude northern girl (6)

I believe the answer is:

violet

I'm a little stuck... Click here to teach me more about this clue!

'girl' is the definition.

I can't explain the remainder of the clue.

(Other definitions for violet that I've seen before include "Rainbow colour; flower" , "See 9" , "Reddish blue colour" , "Shade of purple" , "A flower for a girl" .)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app