Short answer
It means the tokens that represent the trading pool (LP tokens) have been burned or locked, so the creator can't withdraw the pool and leave buyers with nothing to sell into.
When a token trades on a decentralized exchange, it sits in a pool alongside SOL or a stablecoin. Whoever provides that pool receives LP tokens that let them withdraw it later. If the creator holds those LP tokens freely, they can pull the pool at any moment.
Burning LP tokens destroys that ability permanently. Locking them in a time-lock contract delays it until a set date. Either way, the share of liquidity that's burned or locked is a useful number; DYOR shows it on every token.
Locked liquidity protects against one kind of rug. It doesn't stop insiders from selling their tokens into the pool, which can be just as damaging.
See the checks for yourself
18+ only. Self-custodial: you keep your keys. 0.5% per trade, no minimum. Memecoins can go to zero.