unstable

ADJECTIVE:

1. not stable; not firm or (firmly) fixed; not constant; unsteady.

2. liable to fall or sway.

3. unsteadfast; inconstant; wavering:
unstable convictions.

4. marked by emotional instability:
an unstable person.

5. not steady in action or movement; irregular (in movement):
an unstable heartbeat; an unstable pulse.

6. lacking stability, fixity, or firmness.

7. disposed to temperamental, emotional, or psychological variability.

8. wavering in purpose or intent; vacillating.

9. lacking steadiness; apt to move, sway, or fall:
an unstable tower.

10. liable to change or alteration:
an unstable economy; unstable weather.

11. characterized by lack of emotional control.

Examples:

An unstable nuclear reactor core // the minute we put the books down on the unstable desk, the whole stack went crashing to the floor.

Origin:

Middle English word dating back to 1175–1225; see origin at un-1, stable2. —Dictionary.com. // First Known Use of unstable: 13th century. —Merriam-Webster.

Sources: 1, 2.

Added: 8 June 2020 {6:26 PM} // Updated: 13 July 2020 {11:31 PM}