When someone says they have "run out of steam," it means they have lost momentum, energy, or enthusiasm for a task or activity. But there are several synonyms that can be used to convey the same meaning. For instance, one could say they have hit a wall, run out of gas, reached a dead-end, or hit a snag. Another option might be to say they have lost their drive, hit a slump, or reached a plateau. Whatever the phrase, it is important to recognize when we are running out of steam and take a break or change direction if needed to avoid burnout.