That tends to improve someone or something (especially (dated) to educate or morally better a person).

Capable of being improved. / Capable of being used to advantage; profitable.

Impossible to prove.

Quality of being improvable; capability of improvement.

So as to permit improvement. / In a way that cannot be proven.

To fix, make better or increase the quality of (something) in comparison to previous attempts; to contribute to an ongoing effort to improve (something).

plural of improvization

simple past tense and past participle of improvize

plural of improvability

Third-person singular simple present indicative form of improve