The phrase "rudimentary understanding" means having basic or basic-level knowledge or comprehension about something. It implies only a simple or fundamental grasp of the subject without being thorough or advanced. Full definition
First off, for anyone with even rudimentary understanding of biology and chemistry, calling carbon dioxide pollution is akin to calling oxygen pollution. (wattsupwiththat.com)
Even if you have only the most rudimentary understanding of how the Internet works, you are probably pretty clear on the idea that you do not post privileged information there, and you are certainly clear that ex parte communication with someone you are suing is the worst idea ever. (lawyerist.com)
You could be a Pro with rudimentary understanding of the sport, a beginner ready to get going, or you could be just an ordinary folk wanting to get an up and about physique and a good immune system! (rawbarrel.com)