grok 
(grŏk)
(grŏk)tr.v. grok·ked, grok·king, groks
Slang
Slang
To understand profoundly through intuition or empathy.
[Coined by Robert A. Heinlein in his Stranger in a Strange Land.]
- observation
- observational
- observationally
- observatory
- observe
- observer
- observingly
- obsess
- obsession
- obsessional
- obsessionally
- obsessive
- obsessive-compulsive
- obsessive-compulsive disorder
- obsessive-compulsive personality disorder
- obsessively
- obsessiveness
- obsessor
- obsidian
- obsolesce
- obsolescence
- obsolescent
- obsolescently
- obsolete
- obsoletely