1. She pushes dress standards for modesty to the max or is over the line of Catholic acceptability.
OR
2. She wears the same long skirt and sweater, shawl, or bolero to Mass every Sunday.
3. She's seen in the church parking lot slipping into and out of above clothing over skin tight jeans and a too tight top that is sleeveless, has skinny straps, and plunging neckline.
4. Her 'veil' is a coaster-sized doily that matches her hair color. She slaps it on after plopping in the pew and rips it off en-route to the the door. (Veil, skirt, and cover-up are stored in a bag in the car.)
5. Although physically fit, she does the Novus Ordo Nod instead of genuflecting.
6. She frequents Communion but rarely darkens the confessional door.
7. After Communion, she checks out the guys and women's clothing styles instead of making her thanksgiving.
8. She is often late to Mass, satisfied with slipping into a pew just in time for the Offertory. She leaves before the recessional hymn or rushes out immediately after low Mass, not bothering to thank Our Lord.
9. She prefers parish social events to Mass. At them, she is loud, forward, butts-in to male conversations, swigs beer out of the can or bottle, noticeably checks out eligible men, snubs mothers and pious women, brags about her career or her grades at university. She is annoyed by children and crying babies. She has disdain for large families, especially if they wear hand-me-downs, drive a well-used 10+ year-old van, and cannot afford or choose to not have a TV and the latest technology.
10. She mocks home schooling, refusal of vaccines, preppers, and all who believe in "conspiracy theories."
11. She may use religion as a facade to attract men or gain the favor of the priest in the hope of being granted power and influence.
12. To the above end, she may make a display of performing religious exercises. This takes the form of exaggerated piety---displaying her new expensive Rosary, feigning emotion, loudly singing over the choir, praying aloud at high volume, one syllable ahead of everyone else, just in case others don't know how well she's learned her prayers, blocking the doorway while repeatedly blessing herself with Holy Water, etc.
Gentlemen, if you notice any of these in your girlfriend, quit her and keep looking!