The phrase "dull rules" is correct and can be used in written English.
It refers to rules that are boring or uninteresting. You can use it when talking about a set of rules that are not engaging or exciting. Example: The company's training manual was filled with dull rules and regulations that made it difficult for new employees to stay focused.
In a world of dull rules and miserable anxieties, art is a holiday, a carnival.
It fostered dictatorship along the same, dull rules which the Arabs tolerated for so many years: better autocracy than anarchy, better peace than freedom, better secular than sectarian.
And to those dry and dull rules they've added some good basic information for cycling novices such as how to change a puncture, how to combat saddle soreness and advice on essential bike kit.
I have a very simple, though dismayingly dull, rule governing the purchase of boxed sets: buy only collections by major twentieth-century artists, people whose names you are likely to find in a reputable biographical dictionary.
The editing was dull, the rules were confusing, the emotions felt manufactured.
How Not to Be Wrong: The Power of Mathematical Thinking by Jordan Ellenberg [480 pages, The Penguin Press, 2014; Guardian bookshop; Amazon UK hardcover/paperback/kindle UK; Amazon US hardcover/paperback/audiobook download/kindle US] Publisher's synopsis: The math we learn in school can seem like a dull set of rules, laid down by the ancients and not to be questioned.
Much of what economists know about structural unemployment has been gleaned from the sorry history of continental Europe, where fat benefits and rigid firing rules dulled labour-market efficiency.
Very occasionally, in one class or the other, a glimmer of something vital and truly alive could thrillingly and seemingly out of nowhere suddenly come into being and the sheer exhilaration of possibility would momentarily electrify the room, but that was almost always the exception to the dull and lifeless rule.
This sounds dull, but because these rules serve as barriers to entry in the sector, they can be used by incumbent institutions that control the process to block useful change.
Like language, dating is at its best when playful, and at its dullest when bound by rules.
American fashion is – as a guiding general rule – extremely dull or, to use the preferred fashion lingo, "commercial", and I say this as both an American and someone who likes fashion.
