We'll consult a few dictionaries:

soph·ist
n.
1.
a. One skilled in elaborate and devious argumentation.
b. A scholar or thinker.
2. Sophist Any of a group of professional fifth-century b.c. Greek philosophers and teachers who speculated on theology, metaphysics, and the sciences, and who were later characterized by Plato as superficial manipulators of rhetoric and dialectic.

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1. ancient Greek philosopher: a member of a school of ancient Greek professional philosophers who were expert in and taught the skills of rhetoric, argument, and debate, but were criticized for specious reasoning. The sophists were active before and during the time of Socrates and Plato, who were their main critics.


2. somebody using clever talk to deceive: a deceptive person who offers clever-sounding but flawed arguments or explanations


[Mid-16th century. Via Latin sophista < Greek sophistḗs "master of a craft, man clever in practical affairs," also "cheat" < sophos "skilled in a craft, clever, wise"]