"I would like to take a break."
Because "take a break" is a phrase and if you look up the definition of each word "break" is the only one that would help at all, but even that has a long list of meanings - if Duo listed them all you'd have: 打破, 断, 决裂, 切断, 拆散, 决口... The "hints" can be helpful for somethings but for phases like this they're not really going to help.
I think "to rest" only implies inactivity/ relaxing for an indeterminate period of time (you might resume the activity after or you might do something else) while "take a break" implies a short period of rest and then the activity resumes. And I think that also describes the difference between "休息" and "休息一下".
I ran 休息一下 through a translator the results were 'take a break'. I ran 'I want to rest a little' through the translator the results were '我想休息一下‘. Looks like the same characters may be translated two ways.
As a native english speaker 'taking a break' and 'resting a little', have different meanings. When I take a 'break', I stop the current activity and do something else: stop studying, then go eat a sandwich. When I 'rest' a little, I stop the activity and do no activities: stop studying, then go take a nap.
There must be some way to indicate these differences in Chinese. Can any native Chinese speakers clarify?
Not a native speaker, but I'm pretty the way it works is 一下 "a little" is needed to make 休息 "rest" more finite: "I want to rest" vs "I want to rest for a bit (and then get back to work)". You can think of 休息 here as "rest (from the task at hand)/ stop doing work" rather than, say, sleeping.
That's actually my culture shock when learning "take a break" and "rest a little" has different meaning. In Chinese, 休息 doesn't imply what's the next action so it could mean both depending on context. One word I can think of that is closed to "rest a little“ is "歇一下”, 歇 usually imply you are tired or strained from physical activity and need rest to recover. But people can still say 歇一下, and then start to do another thing that helps them recover.