be careful not to (do something)

be careful not to (do something)

Proceed cautiously, in an attempt to avoid potential problems or pitfalls. This phrase is often said as a warning or instruction. I was careful not to make any noise as I crept into the house after curfew. As you plan your talk, be careful not to bore the audience with scientific terms they won't understand. This plate is very hot—be careful not to burn yourself.See also: careful, not