1) Again and again 2) At every point 3) Ceaselessly 4) Endlessly 5) Incessantly 6) Unceasingly 7) Unendingly 8) With unflagging resolve 1) All day every day 2) Always 3) Around the clock 4) At all times 5) Ceaselessly 6) Constantly 7) Continually 8) Day after day 9) Day in and day out 10) Incessantly 11) On and on 12) Onandonandon 13) Onaon 14) Onend 15) Twenty four seven 16) Unceasingly 17) Unendingly 18) Unremittedly 
• (adv.) In a continuous maner; without interruption.
Con·tin'u·ous·ly adverb In a continuous maner; without interruption. -- 
[adv] - at every point
For a long period of time
adverb at every point; `The function is continuously differentiable`