Bold wife cutting girdle fastening (13)
I believe the answer is:
swashbuckling
'bold' is the definition.
(thesaurus)
'wife cutting girdle fastening' is the wordplay.
'wife' becomes 'w'.
'cutting' is an insertion indicator (some letters cut their way into a word).
'girdle' becomes 'sash' ('sash' can be a synonym of 'girdle').
'fastening' becomes 'buckling' (buckling is a kind of fastening**).
'w' going inside 'sash' is 'swash'.
'swash'+'buckling'='SWASHBUCKLING'
(Other definitions for swashbuckling that I've seen before include "Full of bravado" , "Taking part in daring adventures" , "Dashing" , "Flamboyantly adventurous" , "Daredevil" .)