erratic
adjective
1. liable to sudden unpredictable change
- erratic behavior
Similar word(s): changeable, changeful, fickle, mercurial, quicksilver
2. having no fixed course
- an erratic comet
Similar word(s): unsettled, planetary, wandering
3. likely to perform unpredictably
- erratic winds are the bane of a sailor
Similar word(s): undependable, unreliable, temperamental
Sentences with erratic as an adjective:
- Henry has been getting erratic scores on his tests: 40% last week, but 98% this week.
- erratic conduct
noun
1. (geology) A rock moved from one location to another, usually by a glacier.
2. Anything that has erratic characteristics.