1) Constant 2) Continuous 3) Incessant 4) Never-ending 5) Nonstop 6) Perpetual 7) Unceasing 8) Unending 9) Uninterrupted 10) Unremitting 11) Without stop 12) Without stop or pause 1) Continuous 2) Endless 3) Eternal 4) Everlasting 5) Incessant 6) Nonstop 7) Unending 8) Unlimited 9) Unremitting 
• (adv.) Without intermission or end. • (a.) Without pause or end; incessant.
Cease'less adjective Without pause or end; incessant. 
[adj] - uninterrupted in time and indefinitely long continuing
constant adjective uninterrupted in time and indefinitely long continuing; `the ceaseless thunder of surf`; `in constant pain`; `night and day we live with the incessant noise of the city`; `the never-ending search for happiness`; `the perpetual struggl...
continual
without stop or pause; unending; incessant.