Meaning:

Literally meaning “locked,” this term is used as a metaphor to describe a close and firm relationship between two persons, usually couples or very good friends. Very often, fans use the term to discuss gossips about celebrities.

Example:

A: 听说你弟弟找了个漂亮女朋友，这次打算稳定下来了吗？

Tīngshuō nǐ dìdi zhǎo le gè piāoliang nǚpéngyou，zhècì dǎsuàn wěndìng xiàlái le ma？

They say your younger brother has got a pretty girlfriend. Is he ready to settle down?

B: 目前看他俩是锁了。可年轻人的感情谁知道呢？

Mùqián kàn tāliǎ shì suǒle。Kě niánqīngrén de gǎnqíng shuí zhīdào ne？

At present they are in a stable relationship. But who can predict the future about these kids?