unstable

Everyday

1. Likely to fall over, move or break; not steady. tree →
2. Likely to change suddenly: unstable weather or prices. tree →
3. (science) Likely to change or break down into something else: an unstable chemical. tree →
4. (of a person's mood) Changing quickly and hard to predict. tree →

In the lessons

In science and design lessons: a tall thin tower is unstable; a wide base makes it stable. In safety: unstable cliffs, ice or ladders are dangerous. In news: unstable prices or governments. Phrases: «unstable ground», «emotionally unstable».

Examples

• The tower of blocks was unstable and fell over. tree →
• Keep away from the unstable cliff edge. tree →
• The ice on the pond is unstable, so don't walk on it. tree →
• Some chemicals are unstable and can explode. tree →
• Food prices have been unstable this year. tree →
• A three-legged stool with one short leg is unstable. tree →

Note

Takes «an». Opposite: stable, steady. Science fact: a lower centre of gravity and a wider base make things more stable. Calling a person «unstable» is a serious and often unkind label.

In Jewish tradition

In Jacob's blessing, Reuben is "unstable as water," meaning hasty and not steady.

Interpretation. Jacob says Reuben loses his place as firstborn because of the wrong he did. The tradition reads his lack of self-control as the reason he loses leadership.

Examples

• Unstable as water, have not thou the excellency; because thou wentest up to thy father's bed; then defiledst thou it — he went up to my couch. (Torah GEN.49.4, JPS 1917) tree →

Note

Takes «an». Opposite: stable, steady. Science fact: a lower centre of gravity and a wider base make things more stable. Calling a person «unstable» is a serious and often unkind label.