A bold pose transformed this dance (4,5)
I believe the answer is:
paso doble
'this dance' is the definition.
(paso doble is a kind of dance)
'a bold pose transformed' is the wordplay.
'transformed' indicates an anagram.
'a'+'bold'+'pose'='aboldpose'
'aboldpose' with letters rearranged gives 'PASO DOBLE'.
(Other definitions for paso doble that I've seen before include "Fast Latin American ballroom dance" , "Two-step (music)" , "Steps" , "Bullfight music - ape's blood (anag)" , "Marching music" .)