"Witness” group (5)
I believe the answer is:
amish
'witness group' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for amish that I've seen before include "those eshewing modern technology" , "US religious community" , "American follower of the Mennonite religion" , "Of US Mennonites" , "Relating to a strict US Mennonite sect" .)