Insidious and Underhand

Insidious

Insidious adjective - Working or spreading in a hidden and usually injurious way.

Underhand is a synonym for insidious in secretive topic. In some cases you can use "Underhand" instead an adjective "Insidious", when it comes to topics like stealthy. popular alternative

Nearby Word: insidiously

Underhand

Underhand adjective - Given to or marked by cheating and deception.
Usage example: willing to stoop to underhand methods in order to win

Insidious is a synonym for underhand in sly topic. You can use "Insidious" instead an adjective "Underhand", if it concerns topics such as deceitful, secretive. popular alternative

Nearby Word: underhanded
Cite this Source
Underhand and Insidious. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/insidious/underhand
Insidious & Underhand. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/insidious/underhand>.
Underhand or Insidious. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/insidious/underhand.
Google Ngram Viewer shows how "insidious" and "underhand" have occurred on timeline