1. A reference to physically allowing the passage of radiation, or X-rays, to go through objects: The nonopaque radiation procedures make it possible for X-rays to be radiolucent or to allow the passage of radiant energy to go through materials so they are not blocking the process.
2. Not being difficult to understand; and so, being clear and obvious: The nonopaque language of the scientist made it possible for the non-scientific audience to understand what he was talking about.