Something that, or someone who, improves something. / (obsolete) Specifically, a person who improves land or property, a landscaper.

plural of improver

(transitive) To make (something) better; to increase the value or productivity (of something). / (intransitive) To become better. / (obsolete) To disprove or make void; to refute.

The act of improving; advancement or growth; a bettering

plural of improvement

(informal) Improvisation. / (acting) A form of live entertainment characterized by improvisation and interaction with the audience.

To perform improv.

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

present participle of improve

That has been made better; enhanced.