Meaning:
“弄” is short for “糊弄 (húnòng),” which means “to fool” or “to give someone the runaround,” and “子” is a suffix meaning “a person” (for example: 胖子, pàngzi, fatty). This term is used to describe those who try to avoid giving a straightforward comment or making a decision so as not to offend others, or who do not treat life very seriously. It derives from “the study group of doodling — how to deal with annoying things that you cannot avert in life,” a discussion group on the Chinese social networking platform Douban whose users are often young people interested in culture and art. In that discussion group, many people share their tricks of giving others the runaround without appearing being impolite.
Example:
A: 上回丽丽答应周末陪我去逛街，一直都找不出空。
Shànghuí lìlì dāying zhōumò péi wǒ qù guàngjiē，yīzhí dōu zhǎobuchū kòng。
Li Li has agreed to go shopping with me some weekend, but she never finds a convenient time.
B: 她是个弄弄子，你还是找别人吧。
Tā shì ge nòngnòngzi，nǐ háishì zhǎo biérén ba。
Instead of saying “No,” she tends to give you the runaround. You’d better ask someone else to go with you.