Can't be moved into quarters with that attitude! (6)
I believe the answer is:
stance
'that attitude' is the definition.
(stance is a kind of attitude)
'can't be moved into quarters' is the wordplay.
'be moved' is an anagram indicator.
'into' is an insertion indicator.
'quarters' becomes 'se' (south and east, two compass quarters).
'cant' is an anagram of 'tanc'.
'tanc' put into 'se' is 'STANCE'.
'with' is the link.
(Other definitions for stance that I've seen before include "Upright posture" , "Golfer's position for making stroke" , "Player's posture for making, say, golf stroke" , "Posture; point of view" , "One's physical or mental attitude" .)