incessant (adj) – unceasing; continuing without interruption
BREAKDOWN: IN- (not) + CES- (yield) + -ANT (tending to)
This word is built on the root CES-, which means to go, to yield, or to withdraw.
Common CES- words include access, ancestor, excess, necessary, necessity, process, recess, and success.
More esoteric CES- words include cession and cesspool.