What it means
It means to bail on a job, team, relationship, or plan when things start looking rough and you'd rather save your own skin than stick around. It usually has a disloyal edge to it, because you're not just leaving, you're leaving other people to deal with the smoke, leaks, and general carnage.
Usage examples
"As soon as the layoffs rumour hit, Dan jumped ship to a competitor and took his mug with him. Now everyone’s polishing CVs."
"Three of the best players jumped ship to richer clubs the week before the final, charming."
"She jumped ship from the startup the moment the funding dried up, can't say I blame her."
"The minute the group chat turned into actual work, he jumped ship and pretended he'd never seen the messages."
"Investors started looking twitchy and half the senior lot jumped ship before the apology post even went live."
Where it comes from
It comes from the old nautical use of jump ship, where a sailor illegally deserted a vessel before the voyage or duty was over. By the 19th century it was firmly tied to abandoning shipmates and obligations. Later it drifted ashore and kept that same whiff of quitting when things turn ugly.
