1) Ceaseless 2) Constant 3) Continual 4) Continuous 5) Endless 6) French word used in English 7) Never-ending 8) Nonstop 9) Often repeated continual 10) Permanent 11) Perpetual 12) Unbroken 13) Uninterrupted 14) Unremitting 1) Ceaseless 2) Continual 3) Continuous 4) Endless 5) Everlasting 6) Repeated 7) Uncessant 8) Unremitting 
• (a.) Continuing or following without interruption; unceasing; unitermitted; uninterrupted; continual; as, incessant clamors; incessant pain, etc.
In·ces'sant adjective [ Latin incessans , -antis ; prefix in- not + cessare to cease: confer French incessant . See Cease .] Continuing or following without interruption; unceasing; unitermitted; uninterrupted; continual; as, incessant clamors; in...
often repeated continual 
The USS Incessant was an American Admirable Class minesweeper of 625 tons displacement launched in 1943. The USS Incessant was powered by diesel engines providing a top speed of 14.5 knots and carried a complement of 104. She was armed with one 3 inch dual-purpose gun and four 40 mm anti-aircraft guns.
[adj] - occurring so frequently as to seem ceaseless or uninterrupted
perpetual adjective occurring so frequently as to seem ceaseless or uninterrupted; `a child`s incessant questions`; `your perpetual (or continual) complaints`
continuing without interruption; ceaseless; unending: an incessant noise.