[JockoManning]

"Grok" IIRC ... was first used in the SciFi Novel:

STRANGER IN A STRANGE LAND

In the novel, it meant to extra intensely, intensely comprehensively, intensely thoroughly KNOW something in an immersive knowing sort of way.

[Publius]

All very true. But later in the novel, it’s explained that the literal meaning is “to drink.”