英汉词典

1. 不定时的;不定期的
    If events or actions occur at irregular intervals, the periods of time between them are of different lengths.

irregular的解释

    e.g. Cars passed at irregular intervals...
           断断续续地有汽车驶过。
    e.g. She was taken to hospital suffering from an irregular heartbeat...
           她因心律不齐被送往医院。