Jeeva or Sajeeva / Jiva / Samadhi also known in Tibetten as the state of Tukdam means "becoming one" with the universal consciousness or merging with the Divine.
It has different terms and is used as different words in different religions. Buddhists call it Nirvana and Christians call it ecstasy or 'merging with the spirit'.
It is a very advanced samadhi state closely related to the nirvikalpa samadhi state but then permanent. In Maha samadhi the body will decay over time and the energy will leave the body upon death. In Jeeva samadhi you cannot say the body dies nor can you say it is still alive, however the energy will remain in and around the body as if it were still alive and the body will not decay over time either (or extremely slowly as in some cases). This is a state where Siddhas enters into the samadhi state at their own will after completion of their mission on earth and their mind completely dissolved into the Divine, They stop the functioning of the body and mind.