Answer:

stickler

Answer	Crossword Clue
STICKLER	Perfectionist
STICKLER	One hard to budge
STICKLER	Strict disciplinarian.

STICKLER	Purist
STICKLER	Difficult problem
STICKLER	Slave to detail
STICKLER	"Perfectionist" label captivates Liberal (8)
STICKLER	Person not easily budged