noun

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

2. Anything that has erratic characteristics.

Synonyms: dropstone

adjective

1. Unsteady, random; prone to unexpected changes; not consistent

   “Henry has been getting erratic scores on his tests: 40% last week, but 98% this week.”

2. Deviating from normal opinions or actions; eccentric; odd.

   “erratic conduct”