erratic

Everyday

1. Not regular or steady; changing suddenly in a way you cannot predict. tree →
2. (geology, noun: an erratic) A large boulder carried far by a glacier and left in a place where that type of rock is not normally found. tree →

In the lessons

In everyday life and stories, erratic behaviour, driving or a heartbeat tells the reader something is wrong or worrying. In science and data, erratic results jump around and are hard to trust. In geography, glacial erratics show where ice once moved. Phrases: «erratic behaviour», «erratic driving», «glacial erratic».

Examples

• The car moved in an erratic way across the lanes. tree →
• Our results were erratic, so we repeated the test. tree →
• The puppy's erratic running made us laugh. tree →
• The Wi-Fi is erratic: it keeps cutting out. tree →
• His erratic moods confused his friends. tree →
• A huge erratic boulder sits alone in the field, left by a glacier. tree →

Note

Adjective (also a noun in geology). Adverb: erratically. Pronounced «i-RAT-ik». Not the same as «error», though related in origin (both from Latin «errare», to wander).