cross one's fingers

• As a gesture of good luck, from the Christian notion of inconspicuously making a sign of the cross as an invocation to God.
• As a gesture of lying, probably from the Schwurhand, a gesture used in some European countries when taking an oath. The right hand is raised with the index and middle fingers extended upwards (somewhat similarly to a V sign but with the thumb on the side). By crossing the two fingers, the oath is thus symbolically broken.

cross one's fingers (third-person singular simple present crosses one's fingers, present participle crossing one's fingers, simple past and past participle crossed one's fingers)

1. To put the middle finger across the index finger, especially:

   She was seen crossing her fingers in the wedding photo.

   1. when wishing for luck, or

      I hope everything turns out OK. I'll cross my fingers for you. / I'll cross my fingers that everything turns out OK.

      • 2011, Jayne Addison, About That Kiss‎, →ISBN:

        “Cross your fingers that the readership loves it.” Joy crossed her fingers.

      • 2011, Bette Greene, Get On Out of Here, Philip Hall‎, →ISBN:

        Well, I reckon that all of us Singing Glenways ain't crossing our fingers for you.

      • 2012, Anne Holt; Tom Geddes, Blind Goddess‎, →ISBN:

        With another huge effort he grabbed the bucket hook again, mentally crossing his fingers for the bolts in the thin plywood to hold.

   2. when telling a lie (and attempting to escape the moral and other consequence of that lie).
      • 2007, Toni White, Ridge Street Home‎, →ISBN, page 5:

        Amanda placed her right hand behind her back and crossed her fingers. Her friend Sarah told her if you cross your fingers behind your back when you tell a lie, it's not a lie. Amanda didn't know if she believed that, but she crossed her fingers anyway.

      • 2011, Carsen Taite, Nothing But the Truth‎, →ISBN:

        “You focus your efforts on managing your prosecutors and show up to try that case. I'll handle the rest.” Ryan nodded assent but crossed her fingers behind her back. She would do more than just show up.

      • 2014, Millie Criswell, Staying Single‎, →ISBN:

        “It's not like I've been having fun,” she lied, crossing her fingers behind her back.

      • 2014, Frank Sousa, The Tree of Young Dreamers‎, →ISBN, page 313:

        He always tried to make sure there wasn't a mirror behind him when he made a promise, and if there was and he couldn't cross his fingers, he just crossed them in his mind and hoped this was as good as the real thing.

      • 1969, Phyllis McCallum, The Vanilla Viking A Three-Act Play for Children‎, page 37:

        AFTON: (CROSSING HER FINGERS) I always tell the truth. See for yourself. From the men's doorway you can see that the fjord is empty.

• 2012, Sally Falcon, A Forever Man‎, →ISBN, page 39:

  For a moment, he thought he might have to cross his fingers for good measure. “Okay,” she finally said, allowing him to breathe again. “I see your point — but platonic friends.” This time he did cross his fingers, for a different reason. “No problem. We'll just be shipboard buddies, that's all.”

• cross one's arms
• cross one's heart
• have one's fingers crossed
• keep one's fingers crossed