A fun look at the origin and meaning of "ruhig" and why the sentence "Sei ruhig laut." actually makes sense. Also: die Ruhe and German for "Leave me alone!"
ruhig, die Ruhe, still, leise
A quick fun look at the meaning of "rasten" and why someone who did some "ausrasten" is far from beingy well rested after.
rasten, die Rast, ausrasten, der Rest, das Resteessen, restlich-, ausruhen