Place a large word in the background of the design, make it very low contrast with the background, and make some foreground elements slightly transparent to show the word through.
If you've got some brand adjectives that you really can't think of ways to represent in your design, you can literally take the word and plaster it on your design. Doing this acts almost as a watermark.
Some elements of the page should be slightly transparent so that the word shows through, but nothing that is visually complicated like a photo, since it'll be hard to see the word and end up looking too messy.
The contrast needs to be really low for the background word, but you can make it much larger so it's still noticed.
This will feel tacky to a lot of people, like a perfume video where a voice whispers a brand word. Be very careful.