Meaning:
Short for “one vs. one,” this is used by Chinese netizens to describe an exclusive romantic relationship in novels. That is, the two in the relationship are loyal to each other, never to be distracted by the appearance of a new love interest. Later, this term has also been used to describe other situations where the customer enjoys an exclusive service from a service provider, such as “one-on-one” tutorship.
Example:
A: 暑假你给孩子安排了什么活动？
shǔ jià nǐ gěi hái zǐ ān pái le shén me huó dòng ？
How have you arranged the schedule for your kid’s summer vacation?
B: 一个书法培训，一个街舞课程，还有一个1v1的游泳课。
Yīgè shūfǎ péixùn，yīgè jiēwǔ kèchéng，háiyǒu yīgè yī v yī de yóuyǒngkè。
I sent him to calligraphy and hip-hop classes, and also a one-on-one swimming course.