(noun, 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


1. (geology) A rock moved from one location to another, usually by a glacier.

2. Anything that has erratic characteristics.