Antonyms of adj semestrial

1 sense of semestrial

Sense 1
semestral, semestrial -- (occurring every six months or during every period of six months)

INDIRECT (VIA periodic) -> aperiodic, nonperiodic -- (not recurring at regular intervals)

Similarity of adj semestrial

1 sense of semestrial

Sense 1
semestral, semestrial -- (occurring every six months or during every period of six months)
       => periodic (vs. aperiodic), periodical -- (happening or recurring at regular intervals; "the periodic appearance of the seventeen-year locust")