clockwork

Short definition from Wiktionary

Noun

1. 1
   A mechanism powered by a coiled spring and regulated by some form of escapement; the power is transmitted through toothed gearwheels and used to drive a mechanical clock, toy, or other device.
2. 2
   The action of behaving mechanically in the manner of a clock.

Adjective

1. 1
   Driven by clockwork.
2. 2
   Very smooth and regular.