Machu Picchu builders (5)
I believe the answer is:
incas
'machu picchu builders' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for incas that I've seen before include "People from Andes who settled in Peru" , "Cain's people in old Peru" , "Old people coming from South America" , "People of ancient Peru" , "Ancient Peruvians" .)