It definitely isn't a greeting, although Groot doesn't seem particularly surprised that Enoch can't seem to understand him. The most advanced translating software in the galaxy hasn't been able to translate the subtleties of his peoples' language, after all. Why would it work here?

Groot eyes the stranger warily. He isn't going to let his guard down entirely, but he'll lower his fists for now. He sneers at the mention of sharing a shelter with... whoever this is.

He doesn't decline, however. Instead, he just slumps his enormous wooden body into a nearby armchair. It's clearly too small for someone his size, but it seems to be holding up under his weight, at least.

"I AM GROOT."