Literally: nine – die – one – live
Alternately: To somehow survive a very seriously dangerous situation. To be alive after escaping a 90% chance of dying.
Notes: This comes to us from the Chu Ci, aka the Songs of Chu (Japanese 『楚辞』 = So ji), an extensive and influential poetic anthology attributed, at least in part, to the Warring States period.
This compound may be expanded into a whole phrase as 九死に一生を得る (kyuushi ni isshou wo eru), “to receive one life out of nine deaths.” There are also a surprising number of variants, such as 十死一生 (juu shi isshou), which changes the chance of death from 9 to 10. Beyond that, though, we find 万死一生 (ban shi isshou), replacing 9 with 10,000, or the quirky 万死九生 (ban shi kyuu shou), respectively replacing 9 and 1 with 10,000 and… 9.