Liable to sudden unpredictable change
English: erratic, fickle, mercurial, quicksilver(a)
erraticEnglish
erratic, fickle, mercurial, planetary, quicksilver(a)
Adjective
Having no fixed course
English: erratic, planetary, wandering
Likely to perform unpredictably, sometimes it would start and sometimes it wouldn't"
English: erratic, temperamental