The Chinese word for brush is
发刷

fà shuā

Chinese Definition

brush
1. 毛刷
2. 刷状物
3. 笔法
4. 狐尾
5. 拂拭
6. 小冲突
7. 丛林
8. 以刷擦
9. 掠过
10. 疾走
11. 刷子
12. 刷
13. 洗刷
Components
发
1. Simplified form of 發
2. Simplified form of 髮
刷
1. brush (tool)
2. to brush; to scrub; to clean with a brush
3. to paint with a brush
4. (colloquial) to eliminate
5. (chiefly Mainland neologism colloquial) to browse through (updates on social media etc.); to flip through
刷手機 - to check one's phone (for updates on social media etc.)
這部電視劇太好看了！我已經開始四刷了！ - This television drama is so good! I have already begun to watch through it for the fourth time!
6. (colloquial) to write; to finish (a massive quantity of works)
7. (video games, transitive) to grind
刷錢 - to grind for in-game money
8. (video games) to spawn
刷車器 - car spawner
9. (dialectal) to pick; to choose

刷子
1. n. brush (implement with a handle)
2. n. (obsolete, informal) fool; idiot

刷
1. brush (tool)
2. to brush; to scrub; to clean with a brush
3. to paint with a brush
4. (colloquial) to eliminate
5. (chiefly Mainland neologism colloquial) to browse through (updates on social media etc.); to flip through
刷手機 - to check one's phone (for updates on social media etc.)
這部電視劇太好看了！我已經開始四刷了！ - This television drama is so good! I have already begun to watch through it for the fourth time!
6. (colloquial) to write; to finish (a massive quantity of works)
7. (video games, transitive) to grind
刷錢 - to grind for in-game money
8. (video games) to spawn
刷車器 - car spawner
9. (dialectal) to pick; to choose

筆
1. writing brush
2. pen; pencil
你有筆嗎？記一下這個電話號碼。 - Do you have a pen to write this phone number?
你這個字寫錯了，這裡少了一筆。 - The character you have miswritten lacks one stroke here.
我會儘jǐn早把這筆錢還huán 給你。 - I will return the money as soon as possible.