erratic

(s) liable to sudden unpredictable change
- erratic behavior
- fickle weather
- mercurial twists of temperament
- a quicksilver character, cool and willful at one moment, utterly fragile the next
mercurial, quicksilver, fickle,
(s) having no fixed course
- an erratic comet
- his life followed a wandering course
- a planetary vagabond
planetary, wandering,
(s) likely to perform unpredictably
- erratic winds are the bane of a sailor
- a temperamental motor; sometimes it would start and sometimes it wouldn't
- that beautiful but temperamental instrument the flute - Osbert Lancaster
temperamental,

mercurial quicksilver fickle planetary wandering temperamental

erratum

erratically