that does not relent; unyieldingly severe, strict, or harsh; unrelenting: a relentless enemy.
Origin: 1585–95; relent + -less
rigid, unbending, obdurate, adamant, unyielding. See inflexible.
January has been "relentless". The snow and cold has been "relentless". It snowed last night.
Another storm is coming tomorrow.
My workload has been "relentless". My boss is "relentless" with meetings, tasks, deadlines........
My in-basket on my desk has spilled over, yet my out-basket is not keeping up.
And the diet.......lets not even go there.