Guide words are the words at the top of each page in a dictionary that tell you the first and last entry words on that page. Without knowing the specific dictionary you're using, it's impossible to give you the exact guide words for the page with "brim."
However, here's how you can find the guide words for "brim":
1. Open your dictionary to the section where you expect "brim" to be. Think about the alphabet and where "brim" falls (between "bright" and "bring").
2. Look at the top of the page. The guide words will be there, usually in bold.
3. The first guide word will be a word that comes earlier in the alphabet than "brim," and the second will be a word that comes later.
For example, the guide words for "brim" might be "bridge" and "broad."