Grok is a bullshit fucking word that people who have been in the tech space too long use to sound cool and obfuscate an otherwise easy concept.
"Do you understand it really well?" is infinitely fucking better than "can you grok that?". The first sentence doesn't have all of the disgusting pretentiousness of a tech interview whiteboarding flame session associated with it, where one person has done the problem 100 times and the other has done it precisely never.