(tending to find and call attention to faults) "a captious pedant"
: marked by an often ill-natured inclination to stress faults and raise objections <captious critics>
: calculated to confuse, entrap, or entangle in argument <a captious question>
The Webster definition seems better in this case, as multiple definitions I have seen say that the word captious has the connotation of annoying faultfinding. Although, the way princeton's definitions work, the same entry is there for faultfinding, so it does make sense that a nuance would be lost.
Pronunciation: Cap as in cap, capture, captcha. Tious sounds like xious in obnoxious. (which captious encapsulates) Alternately, Ti is the sh sound, like shoot, and ious sounds like ess in heiress.