Sentence:  He freely plucks notions and verbiage from science fiction to describe everything from mountain-related undertakings to political subterfuge – like "<WSD>grok</WSD>", a term from Robert Heinlein's Stranger in a Strange Land, to denote intuitive understanding. 
Meaning of the word marked with <WSD> tags:  To understand (something) intuitively, to know (something) without having to think intellectually.