p 1811 on Oxford Latin Dictionary (2012 2 ed) doesn't expound the semantic shift from 1 to 3b below. I read Etymology on "retort".
I don't wrestle or fight, and don't understand Definition 1. Who's wrenching what/who? What's being twisted "round so as to face the opposite direction"?
1 Answer
Retorquere means literally "to wrench or twist back" so in wrestling terms it would mean something along the lines of pulling ones limbs back like getting someone in a leg or arm bar.
The "link" to retort comes in the 2nd, 3rd, and 4th senses, meaning a turning back. A retort is a "comeback" it's turning the argument back on itself. Though it likely originally meant something along the lines of "using one's argument against them" it has come to mean a response or rebuttal in general over time.
I've found many Latin words come into English in a more figurative sense than literal. It's kind of like having to read between the lines.