A kevalin has destroyed the karmas that obstruct knowledge, perception, bliss and energy, though the karmas that sustain the body remain until death. Every tīrthaṅkara is a kevalin, but not every kevalin is a tīrthaṅkara: many attain omniscience without founding a teaching community. At death the kevalin becomes a siddha.
Kevalin
One who has attained kevala jñāna, omniscience, while still embodied.
Also: Kevalin, arhat