Folly of girl touring North America (6)
I believe the answer is:
lunacy
'folly' is the definition.
(thesaurus)
'girl touring north america' is the wordplay.
'girl' becomes 'lucy' (**).
'touring' is an insertion indicator (touring can mean going round).
'north america' becomes 'na'.
'lucy' enclosing 'na' is 'LUNACY'.
'of' is the link.
(Other definitions for lunacy that I've seen before include "Tomfoolery" , "Craziness, madness" , "idiotic act" , "Madness, insanity" , "Extreme folly, insanity" .)