prob-, proba-, probat-, prov-

(Latin: upright, good, honest; to try, to test, to examine; to demonstrate)

disprovable (adjective)
Something which can not be proved.
disproval
Act of disproving; disproof.
disprove (verb), disproves; disproved; disproving
To show that an assertion, claim, etc. is false, invalid, or wrong; to refute; to invalidate.
disprover
1. One who disproves or confutes.
2. A debater who refutes or disproves by offering contrary evidence or argument; rebutter, refuter, confuter.
flameproof
1. Resisting the effect of flames.
2. Not readily ignited or burned by flames.
3. Not likely to burn or to be damaged by fire; such as, flameproof clothing.
foolproof
1. Designed to continue working properly in the face of any kind of human error, incompetence, or misuse.
2. So well thought out that failure is thought to be impossible.
improbability
1. Not likely to be true or to occur or to have occurred.
2. The quality or condition of being improbable; unlikelihood.
3. Something improbable or unlikely.
improbable (adjective)
1. Not probable; unlikely to take place or to be true or to happen.
2. Having a probability too low to inspire belief.
3. Too improbable to be considered believable.
improbably
1. Not easy to believe.
2. Unlikely to take place or be true.
improvable (adjective)
1. Capable of being improved; susceptible to improvement.
2. Capable of being used to advantage; profitable; serviceable; advantageous.
improvably
To advance to a more desirable, valuable, or excellent state.
improve (verb), improves; improved; improving
1. To raise to a more desirable or more excellent quality or condition; to make better.
2. To increase the productivity or value of land or property.
3. To put to good use; to use profitably.
4. To make beneficial additions or changes.
improvement
1. The act or process of improving.
2. The state of being improved.
3. A change or addition that improves.
improver
1. A person or thing that improves.
2. Someone devoted to the promotion of human welfare and to social reforms.
3. A component that is added to something to improve it.
probability
A measure of how likely it is that some event will occur.