inertia

Where does the word "inertia" come from? It comes from Latin iners, and was adopted directly into English (1710s).

Inertia’s story begins in Latin: iners meant “idle, unskilled.” Literally unskilled, idle, from in- (without) and ars (skill). It reached English by 1710s as inertia. Kepler first used it; Newton's first law (1687) described the principle. Today, inertia means the tendency of an object to resist a change in its state of motion.

1. Stage 1 · Latin · ancient iners "idle, unskilled", literally unskilled, idle, from in- (without) and ars (skill).
2. Stage 2 · English · 1710s inertia "resistance to a change in motion or state", Kepler first used it; Newton's first law (1687) described the principle.