休 is a Logical Aggregate, formed from two pictograms: on the left, 亻（人） (literally means a person or people), and on the right, 木 (literally means wood or tree). The two parts combine a picture of a man leaning against a tree to take a rest.
休息 have a rest; rest
Lily explains 休 like this:
The character picture of 休 serves just as a little self-talking story: when feeling so tired (say, after a hard farm work) that you could not even hold up your back straight, you may find a big tree to lean against and take a good rest. However, when ancient Chinese created the character of 休, they didn't mean that a man could take his rest forever after having worked very hard. Instead, 休 actually tells that you may have a rest for a short while in the middle of endless work and then you must come back and keep on with it. So you see, how industrious the Chinese people are; they rest simply for the rest of their work.
That's a wise answer to a tricky quseoitn