Definition of "improver"

He introduced and encouraged manufactures of all kinds; and no inventor or improver of any ingenious art did he suffer to go unrewarded.

1754, David Hume, chapter 2, in The History of England, from the Invasion of Julius Cæsar to the Revolution in 1688‎, volume I, London: T. Cadell, published 1770, page 105

Never did Christmas board display a more goodly and gracious assemblage of countenances: those who were not handsome were, at least, happy; and happiness is a rare improver of your hard-favoured visage.

1876, Washington Irving, “The Christmas Dinner”, in Old Christmas‎, London: Macmillan, page 123

What a song. What an instant mood improver. It’ll make you forget all the tension you had built up […]

2015 December 16, Mitch Feltscheer, “9 best musical duos of all time according to Us The Band”, in Music Feed

[…] may not one say Homer is in this like a skilful Improver, who places a beautiful Statue in a well-disposed Garden so as to answer several Vistas, and by that Artifice one single Figure seems multiply’d into as many Objects as there are Openings from whence it may be viewed?

1716, Alexander Pope, “An Essay on Homer’s Battels”, in The Iliad of Homer‎, volume II, London: Bernard Lintot, page 4

He had been visiting a friend in a neighbouring county, and that friend having recently had his grounds laid out by an improver, Mr. Rushworth was returned with his head full of the subject, and very eager to be improving his own place in the same way; […]

1814 July, [Jane Austen], chapter VI, in Mansfield Park: […], volume I, London: […] T[homas] Egerton, […], page 107

The hotel can also arrange beginner and improver angling lessons with a local instructor.

2011 August 27, “Stay the Night: The Blackaddie Hotel, Sanquhar”, in The Independent

The biggest improvers over the last year, according to the index were Côte d’Ivoire, Egypt, Saint Vincent and the Grenadines […]

2014 December 3, Charlie Taylor, “Ireland improves to 17 out of 175 countries on corruption index”, in The Irish Times

The last-named player was given outings in three of the four Tests against England recently, and although plenty of rough edges remained understandably apparent, he gave the impression of being a willing learner and improver.

2016 January 28, Rob Houwing, “Piedt making quiet SA strides”, in Sport24

Soy flour is often added to bread as an improver. It helps the dough texture and can make the bread quite soft.

2016 August 6, Wendyl Nissen, “Who kneads so many ingredients?”, in The New Zealand Herald

When planting a new olive tree, mix organic soil improver and fertiliser into the planting hole and keep the soil moist while the olive establishes itself.

2017 February 7, “Gardening: Get a taste of the Mediterranean”, in The Northern Star