Gut-check Luke Share definition Flag The friend that backs up your gut vibes when you’re about to make a bad choice on a dating app because you’ve let emotions or desperation take over. A: I don’t know if this person is crazy or amazing.B: Well, what did your Gut-check Luke say? Gut-check Luke by TreeHuggerLove November 6, 2019 Get the Gut-check Luke mug.