adj.
1 continuing, continued, continuous, continual, ceaseless, unbroken, uninterrupted, constant, perpetual, non-stop, relentless, persistent, unending, endless, interminable, running:
There has been an ongoing dispute with the museum over the authenticity of the sculpture
2 developing, evolving, growing, successive, unfolding, progressing, progressive:
Rather than come to a hasty decision, we decided to monitor ongoing developments.