翻墙

Literally 'to climb over the wall' - the 'wall' being the 防火长城 (Great Firewall of China). Coined in the mid-2000s after authorities began blocking foreign sites. A close cousin is 科学上网 ('scientific internet access'), a slightly more euphemistic phrase used to dodge keyword filters.

Sensitive vocabulary. Usable among friends, on private chats, and in foreign-language contexts, but risky to search openly on mainland platforms. 梯子 ('ladder') is a common code-name for a VPN tool used to 翻墙.