Bluenoses

4 clues
Prigs
Puritans
Strait-laced ones
Holier-than-thou types
Similar answers:
Ablue
Abluent
Afroblue
Againstthineownbluesky
Aliceblue
Amiblue
Andblue
Apatchofblue
Aquablue
Areblue
Arebluewinteris
Atebluegrass
Avioletisntblue
Azoblue
Azureblue
Babethebluefox
Babetheblueox
Babyblue
Babyblues
Bellblues