The phrase "in someone's hands" is often used to describe a situation where someone is in control or has the power to influence the outcome. Some synonyms for this phrase include "under someone's control," "at someone's mercy," "in someone's possession," "at someone's disposal," and "in someone's grasp." These words describe different ways in which someone can have control over a particular situation or person, ranging from having complete control to having some level of influence or power. Regardless of the specific word used, the phrase "in someone's hands" signifies a situation where the outcome is dependent on the actions of the person in control.