- periodic, periodical - happening or recurring at regular intervals
Antonyms: aperiodic, nonperiodic, noncyclic, nonoscillatory
- periodic - recurring at regular intervals
Antonyms: unrhythmical, unrhythmic (indirect, via rhythmical)
- periodic - recurring or reappearing from time to time; "periodic feelings of anxiety"
Antonym: continual (indirect, via sporadic)