Agrees with boringly orthodox people (7)
I believe the answer is:
squares
This might be a double definition.
'agrees' is the first definition.
(squaring is a kind of agreeing)
'boringly orthodox people' is the second definition.
'squares' can be an answer for 'people'. I am unsure of the 'boringly orthodox' bit.
'with' is the link.
Can you help me to learn more?
(Other definitions for squares that I've seen before include "Equal-sided rectangles" , "Spaces you fill in!" , "Old-fashioned types" , "1,4,9, ..." , "Letters go here" .)