underhanded

Underhanded is an adjective used to describe actions, tactics, or behavior that are dishonestly secretive or deceitful, typically aimed at gaining an advantage while avoiding scrutiny. It implies a violation of fair play or accepted norms, often through sly methods or concealment rather than straightforward, transparent conduct.

Its origin lies in the phrase underhand, originally referring to throwing or delivering an action from below the shoulder with the hand. Over time, the sense broadened to cover dishonest or covert practices, yielding the modern figurative use of "underhanded" to characterize scheming or unscrupulous behavior.

The term is common in discussions of politics, business, and everyday life. It is generally pejorative and can modify nouns such as "tactics," "dealing," "trick," or "scheme" (e.g., underhanded tactics, underhanded dealing). People may describe a compliment as "underhanded" in some contexts, though the more common term for a compliment with an insult is "backhanded" or "backhanded compliment."

Underhanded conveys a covert or sneakily unethical dimension, as opposed to simply unfair or unethical. Synonyms include deceitful, duplicitous, unscrupulous, sly, and shadowy; antonyms include aboveboard, fair, legitimate, and transparent.

Related concepts include underhandedness, covert operation, and backhanded remarks.