beyond/outside your ken
outside (one's) ken
Advanced beyond one's ability to understand or make sense of the subject matter or task at hand. The stuff they're teaching in this advanced math class is outside my ken.
beyond your ken
If something is beyond your ken, you do not know about it or understand it. The quirks of the antiques business were beyond his ken. The scientific subject matter is beyond the ken of the average person. Note: `Ken' here means the full range of someone's knowledge or understanding. The Scottish verb `ken' means `know'.
beyond your kenoutside your range of knowledge or understanding.
beyond/outside your ˈken(old-fashioned) not within your knowledge or understanding: Such things are beyond my ken.
Ken is an old word for ‘knowledge’.