When someone posts thoughts or memes to social media in an attempt to indirectly make fun of, or cause grief to someone, with the hope's that the person will see it when they check your social media.
Yo, did you see that meme on Karen's Facebook?
She's totally Shadow Stabbing at her Ex...
Like Sneak Dissing, but in the form of memes or other social media posts usually directed to an Ex Friend or partner you had a relationship with.
This usually is done after the target person has unfriended your online, so they'll still see it.
However, the Shadow Stabber's Friend's are unaware that it's directed to someone specific.
Yo, did you see the meme that girl posted online?
She's totally Shadow Stabbing at her Ex lmao!