Waivers
NBA teams can release a player to the waiver wire, where he can stay for 48 hours (during the regular season). While he is on waivers, other teams may claim him, for his existing salary. If he is not claimed, he is said to have "cleared waivers", and is treated like any free agent, able to sign with any team (with the special restriction noted above for players who were traded and then waived).
Read more about this topic: NBA Salary Cap