Over a barrel is a phrase that describes a situation where someone has been placed in a difficult position or is at the mercy of someone else. Some synonyms for this phrase include being in a bind, stuck in a tough spot, or being caught between a rock and a hard place. Other expressions that convey a similar idea include being up against it, being in a jam, or being in a tight spot. No matter what words are used to describe this situation, the feeling of being over a barrel is never pleasant, and people often feel helpless and vulnerable when they find themselves in such a predicament.