Select the most appropriate meaning of the given idiom.

To get into hot water

To get into trouble

The most appropriate meaning of the idiom "to get into hot water" is to get into trouble. This idiom is often used to describe a situation where someone has done something wrong or has made a mistake, and is now in danger of being punished or criticized. For example, you might say "I got into hot water with my boss when I forgot to file my paperwork."

The other possible meanings of the idiom are not as common. "To go together" means to be compatible or to match well. "To be expert" means to have a lot of skill or knowledge in a particular area. "To take part" means to participate in something.