Incessant

[Sarah]

Continuing or following without interruption; unceasing;unitermitted; uninterrupted; continual; as, incessant clamors;incessant pain, etc.Against the castle gate, . . . Which with incessant force and endlesshate, They batter'd day and night and entrance did await. Spenser.

[Sarah]

Adjective describing something that happens again and again; ceaseless, interminable.

[Dave Paprocki]

(of something regarded as unpleasant) continuing without pause or interruption.

[PussyCat]

never stopping, especially in an annoying or unpleasant way: