Meaning:
“工具” means “tools,” and “人” means “a person.” Coined by Chinese netizens, this term, literally meaning “a person used as a tool,” can be used differently depending on the context. One common usage is to refer to those who have an unrequited love for another and therefore are ruthlessly used as a tool by their love interest. The other common usage is when people refer to characters in a movie or TV show who are not given enough detailed characterization for audiences to relate to them, but are only used as a tool to propel the plotlines. These roles are often stereotyped and labeled.
Example:
A: 金庸的武侠小说哪里都好，就一点不好。
Jīnyōng de wǔxiá xiǎoshuō nǎlǐ dōu hǎo，jiù yīdiǎn bùhǎo。
Jin Yong’s wuxia (martial arts) novels are superb except for one thing.
B: 哪里不好？
Nǎlǐ bù hǎo？
What’s that?
A: 女性角色都是恋爱工具人，不像男主角一路成长。
Nǚxìng juésè dōushì liàn’ài gōngjùrén，búxiàng nánzhǔjué yīlù chéngzhǎng。
The female roles always serve the single function as someone’s love interest, but are not given the chance to grow and evolve like the male roles.