"Hij is ongerust over de toets."
Translation:He is anxious about the test.
He is not calm about the test would be Hij is onrustig over de toets. Although they look alike, ongerust and onrustig have different meanings. I don't know about their origins, but I can imagine (on)gerust and (on)rust have a similar root and their meanings drifted apart over time.
- ongerust = worried, concerned or anxious
- gerust = confident, comfortable, (re)assured
- onrustig = restless
- rustig = calm
uitgerust = well rested
Het gaat slecht met de economie, ik ben ongerust = The economy is hurt, I am worried
- Ik belde mijn vrouw om te zeggen dat alles goed gaat, nu is ze weer gerust = I called my wife to say everything is well, now she is reassured again
- Het meisje kan niet stilzitten, ze is erg onrustig = The girl can't sit still, she is very restless
- Het waaide niet, de zee was kalm = There was no wind, the sea was calm
- Ik heb uitgeslapen, ik ben uitgerust = I slept long, I am well rested
Funny, I feel the opposite. Unsettled and uneasy are about equal in my mind. Not quite as serious as anxious, more like there is something in the back of one's mind gnawing at one...
I'm not an expert, but because it's been four months without an answer, I'll take a shot. I think they are somewhat related concepts, but "bezorgd" is more like "concerned," and "ongerust" is more like "disquieted." I believe someone who is ongerust is almost certainly bezorgd, but not necessarily vice versa. That is, you can be worried or concerned about something without feeling any adverse (unsettling, disquieting, anxious) effects.