Definition of erratic in English:



  • Not even or regular in pattern or movement; unpredictable.

    ‘her breathing was erratic’
    • ‘Other grandparents fear the regular and erratic comings and goings and demands of the unfit parents of their grandchildren.’
    • ‘The vehicle he was driving was stopped because of an erratic driving pattern typical of someone under the influence.’
    • ‘I did not know then that he had an erratic sleep pattern.’
    • ‘Now scientists say the warming trend, if it continues, will increase the erratic weather patterns.’
    • ‘Global warming is also implicated in increasingly erratic arctic weather patterns.’
    • ‘My sleep patterns have been so erratic this week that I've felt physically sick at times.’
    • ‘A wave of hands suddenly rose high in the air as each one moved about in erratic and unpredictable movements, each as unique as the children's personality.’
    • ‘Steady breezes create regular rollers, while erratic squalls thrust up chaotic surges.’
    • ‘The season of mists and mellow fruitfulness is upon us, but the erratic weather pattern has ensured there is still a lot of corn to cut and straw to gather.’
    • ‘He still has this erratic speech pattern, the fluttering of the eyes, and he's the most appalling speechmaker.’
    • ‘About 50 minutes later, just as people outside realized there was a problem, the elevator stopped its erratic movements.’
    • ‘Room's movements were becoming more erratic and convulsive, and he seemed to have entered a trance-like state.’
    • ‘Of course, if that kind of erratic weather pattern appeared during winter, then I guessed that a blizzard would appear.’
    • ‘Just take for instance, the erratic rain pattern that hit parts of the country in the last farming season.’
    • ‘Rapid eye movement sleep is characterized by a highly erratic breathing pattern and could not be simulated with current technology.’
    • ‘I think I prefer to see him as one of those ageing mongrels one sees with creaky back legs, white whiskers and erratic bowel movements.’
    • ‘The Alice Springs district is dry for much of the year, and has an erratic rainfall pattern, with a slight summer maximum.’
    • ‘As the herd gained momentum the bells on the lead cows rang out louder and the erratic clanging became a regular tolling.’
    • ‘Her blood pressure resumed its former erratic pattern.’
    • ‘I tried for a few photographs to show my appreciation but there was a frisky breeze, too light to notice if it were not for the constant erratic movement of flowers and leaves.’
    unpredictable, inconsistent, changeable, variable, inconstant, uncertain, irregular, unstable, turbulent, unsteady, unsettled, unreliable, undependable, changing, ever-changing, volatile, varying, shifting, fluctuating, fluid, mutable, protean, fitful, wavering, full of ups and downs
    mercurial, capricious, whimsical, fickle, flighty, giddy, impulsive, wayward, temperamental, highly strung, excitable, moody
    blowing hot and cold
    fluctuant, changeful
    View synonyms


  • A rock or boulder that differs from the surrounding rock and is believed to have been brought from a distance by glacial action.

    • ‘The rocks weighed about 40 kg and included two large pieces of unaltered vesicular basalt with many small attached organisms and numerous smaller rocks including a few glacial erratics.’
    • ‘I stayed off the glacier, stumbling down the left moraine, often catching myself with my arms just before slamming into glacial erratics.’
    • ‘The road itself twisted and contorted as much as the river as it dodged through and around clusters of trees and boulders: indigenous and erratics.’
    • ‘In the absence of other sources of building stone, glacial erratics have been extensively used in Finland and northern Poland.’
    • ‘Huge glacial erratics, boulders unlike most of the other rocks in their surroundings, stand in mute testimony to their cross-country transport by advancing ice.’


Late Middle English: from Old French erratique, from Latin erraticus, from errare to stray, err.