Underhanded means doing something in a sneaky, dishonest way, especially when you're trying to hide what you're really doing. When someone uses underhanded tactics, they work behind the scenes in ways that feel unfair or deceptive, avoiding open confrontation or honest methods.

Imagine a student who spreads false rumors about another candidate during a class election, or someone who sabotages a teammate's project so their own work looks better by comparison. These are underhanded actions because they involve trickery and secrecy rather than honest competition.

The word carries a strong sense of disapproval. Underhanded behavior involves scheming that violates trust and fair play. A business might use underhanded methods to hurt competitors, like secretly stealing their ideas or spreading lies about their products.

The opposite of underhanded is aboveboard or straightforward: doing things openly and honestly where everyone can see.