a.k.a. phubber, phubbee, phubbed, double phubbing
To be "snubbed" by your partner or someone in your vicinity in favor of checking social media, texts, email, or news on a smartphone. If two people are doing it to each other, it is called "double phubbing."

Historical perspective: By October 2017, a growing number of Americans said their relationships are being wrecked by a seductive third party. Not another person, but something far more eye-catching: a smartphone, observed by Theunis Bates in The Week. As Stanford University psychologist Emma Seppala explained in The Washington Post, studies show that many couples are struggling to balance their love for each other with their love for their iPhones and Androids. Researchers at Baylor University surveyed some 140 people and found that almost half had been “phubbed” by their partner—that is, snubbed in favor of checking social media, news, or texts on a phone—and that half of those said phone overuse was causing conflict with their loved one. Even if a phone isn’t in use, it can still cause problems. Studies show that simply having a phone out on a restaurant table, for example, interferes with your sense of connection to your dining partner—perhaps because their eyes keep flicking at the device for new alerts, suggesting that piece of technology is more interesting than you.

I’ve been both a phubber and phubbee‚ so I get why this habit is so infuriating and yet so difficult to stop doing. We’re social beings who crave connection, but face-to-face communication can feel passé when there’s a whole world to observe and interact with on our gadgets. Tap a screen and you’re rewarded with an always-updating stream of photos from family and friends, tweets from the president, breaking news, and videos of skateboarding cats. Dipping into that stream lights up the pleasure centers in our brains—the same ones activated by recreational drugs—so we keep going back for more. But that buzz often comes at the expense of genuinely rewarding moments of in-person intimacy, like chatting with a loved one over a morning cup of coffee instead of phubbing them as you scan your Facebook feed. To communicate meaningfully, we have to learn to put down our communication devices.
NetLingo Classification: Online Jargon