Which word indicates an act of deception related to financial gain?

The word "swindle" refers to the act of deceiving someone, particularly for the purpose of financial gain. It involves tricking or defrauding an individual or entity into giving up money or valuable assets under false pretenses. This term captures the essence of deception with an emphasis on monetary or material benefit, making it the most suitable choice for the question.

The other options lack this specific connotation related to deception for financial purposes. "Infallible" describes something that is incapable of making mistakes or being wrong. "Succumb" means to yield to a superior force, typically in the context of giving in to pressure or temptation. "Vanquish" refers to defeating someone or something completely, especially in a fight or competition. Thus, while these words may convey powerful meanings, they do not align with the theme of financial deception as precisely as "swindle."