1. encounter someone/something unexpectedly, reach a large amount
run into someone you know/some problems
To 'run into' is a phrasal verb with a number of meanings. To 'run into' can mean to collide with or impact something. "The car ran into a cyclist." If you run into someone it means you encountered them by chance. "I ran into your sister on the way home yesterday." You can also say you have 'run into a problem' or 'run into difficulties' if you are experiencing a challenge or a setback. "We ran into a few problems during our meeting." You can use 'run in' to talk about amounts or reaching a level of something. "We ran into a colossal amount of dept." "The amount owed has now run into the thousands." With liquids, like paint you can say 'the colours ran into each other' to talk about colours blending into each other or becoming indistinguishable. This use can also be figurative to talk about things becoming blurry or difficult to distinguish or see. "I became dizzy and the people in front of me ran into each other." "The words on the page ran into each other."