incessant

continuing without stopping

Roots

ced / cess / ceed: go, approach, yield, move back, or stop
im- / in- (not): not or without

Other words with the ced / cess / ceed root

accessible: easy to reach or understand
cease: to stop
cede: to yield or give up control
concede: to admit or yield
intercede: to plead or act on behalf of another
precede: to come before
precedent: an earlier example that guides later cases

In- negates cease. Incessant sound, pain, or worry does not stop.

The incessant drilling made quiet study impossible.

Incessant is tiring because the stop never arrives. The root contrast is direct: cease is the silence after motion; incessant is motion that keeps pushing through the silence.