Bolt in is a phrasal verb that means to enter something quickly and abruptly. There are many synonyms for this term, including barge in, burst in, storm in, rush in, and charge in. These words all convey a sense of abrupt entrance and can be used interchangeably in many contexts. Other synonyms for bolt in might depend on the specific situation, such as sneak in, creep in, or slide in, which would imply a more stealthy entrance. Whatever the chosen synonym, the idea of sudden intrusion is always at the heart of the phrase "bolt in".