Meaning:

    Literally “备胎” means a “spare tire.” Unlike in English, where the term is used jokingly to refer to the extra fat on a person’s waist, Chinese netizens have given it a new meaning, which is more associated with the “spare parts” meaning. If a girl hangs out with a guy but does not take him as her boyfriend, that guy would be her “spare tire.” Girls who already have a boyfriend sometimes keep a “spare tire” too. That guy can be her “plan B.”

    Example:

    A: 周末干什么？

    Zhōumò gànshénme?

    What’s your plan for the weekend?

    B: 莉莉要我陪她去逛街。

    Lìli yào wǒ péi tā qù guàngjiē。

    Lili asked me to go shopping with her.

    A: 你又不是她男朋友，干嘛要陪她去？

    Nǐ yòu búshì tā nánpéngyǒu, gànmá yào péi tā qù?

    You are not her boyfriend. Why go with her?

    B: 她对我很好，我不好意思拒绝。

    Tā duì wǒ hěn hǎo, wǒ bùhǎo yìsī jùjué。

    She is nice to me, and I don’t have the heart to say no.

    A: 醒醒吧，她的男朋友是高富帅，她才不会看上你呢。

    Xǐngxǐng ba, tā de nánpéngyǒu shì gāofùshuài, tā cái búhuì kànshàng nǐ ne。

    Wake up. Her boyfriend is tall, rich and handsome. She will never fall for you.

    B: 我喜欢她，当备胎也可以。

    Wǒ xǐhuan tā, dāng bèitāi yě kěyǐ。

    I like her, and am willing to be a stand-by for her.