"Underhanded" refers to actions that are secretive and often dishonest, typically aimed at achieving personal gain at the expense of others. This behavior can involve manipulation, deceit, or trickery, making it difficult for others to recognize the true intentions behind the actions. Such deceptive practices can occur in various contexts, including business, politics, and personal relationships. Individuals who engage in underhanded tactics may use lies or half-truths to mislead others, ultimately undermining trust and integrity in their interactions.