Writing Chinese Characters

The 4 most ancient words which are simultaneously radicals (so they can be parts of other characters).

*Note that character and radical are not the same things, a character has a meaning, a radical, though usually doesn't (except the ancient and the simplest ones). 

人[rén]

1. noun - human being
我是人。
[Wǒ shì rén]
I'm human.
2. noun -  person
军人
[jūnrén]
soldier
3. noun -  everybody
这个孩子人见人爱。
[Zhège háizǐ rénjiànrén'ài.]
Everyone who sees this child likes him.
5. noun [pl] - other people 
我们要真诚待人。
[Wǒmen yào zhēnchéng dàirén.]
We must treat other people with honesty.

火[huǒ]

1. noun - fire
2. noun - ammunition
3. noun - internal heat
4. noun - rage
5. verb - be in a rage
6. adjective - flaming red
7. adjective - prosperous
8. adverb - urgently

木[mù]

1. noun - tree
2. noun - wood
3. adjective - numb
天太冷，我的脚都冻木了。
[Tiān tài lěng，wǒ de jiǎo dōu dòngmùle.]
It's freezing, my feet are numb with cold.
4. adjective - stupid

日[rì]

1.    noun - sun 
日出 [rìchū]
sunrise
日落 [rìluò]
sunset
2. noun - daytime
他们日夜不停地赶路。
[Tāmen rìyè bùtíng de gǎnlù.]
They travelled onwards, not stopping during the day or at night. 
3. noun - day (synonym of 天)
明日[míngrì]
tomorrow
4. noun - [pl] days
  往日 [wǎngrì]
      the past
5. noun - day   
生日 [shēngrì]
      birthday
6. noun - Japan from 日本 [rìběn]
日货 [rì huò]
Japanese goods