IPA: //ˈspiːʃəsli//
KK: /ˈspē-shəs-lē/
In a way that seems true or correct but is actually false or misleading.
The argument was presented speciously, making it difficult to see the flaws in the reasoning.
Speciously → It is formed from "specious" (from Latin *speciosus*, meaning attractive or having a pleasing appearance) and the suffix "-ly" (meaning in a manner of). The word "speciously" means in a manner that appears to be true or correct but is actually misleading or deceptive.
Think of something that looks 'attractive' or 'pleasing' ('specious') but is actually misleading — that's what it means to do something 'speciously'.