We also find Jesus using metaphorical language to describe the fate of those who reject God’s love. He speaks of “outer darkness” (Matthew 8:12, 22:13, 25:30) and the “fiery furnace” (Matthew 13:42, 50), vivid images that convey the pain of separation from God and the consequences of sin.Rich Man and Lazarus (Luke 16:19-31). While Hades in Greek mythology referred to the underworld, in Jewish thought it was often associated with the realm of the dead. Jesus used this concept to speak of a place of torment for the unrighteous after death.

https://www.gotquestions.org/Jesus-teaching-on-hell.html

Jesus primarily used the Greek word “Gehenna” when referring to hell. This term appears 11 times in the New Testament, and in all but one instance, it is spoken by Jesus himself. Gehenna was a reference to the Valley of Hinnom, a place outside Jerusalem that had a dark history as a site of child sacrifice and later became a garbage dump where fires burned continually.