improver (plural improvers)

1. Something that, or someone who, improves something.
   • 1754, David Hume, The History of England, from the Invasion of Julius Cæsar to the Revolution in 1688, London: T. Cadell, 1770, Volume I, Chapter 2, p. 105,

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

   • 1876, Washington Irving, Old Christmas, London: Macmillan, “The Christmas Dinner,” p. 123,

     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.

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

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

2. (obsolete) Specifically, a person who improves land or property, a landscaper.
   • 1716, Alexander Pope, “An Essay on Homer’s Battels” in The Iliad of Homer, London: Bernard Lintot, Volume II, p. 4,

     […] 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?

   • 1814 July, [Jane Austen], chapter VI, in Mansfield Park: A Novel. In Three Volumes, volume I, London: Printed for T[homas] Egerton, […], OCLC 39810224 ↗, page 107 ↗:

     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; {{...}

3. One who improves his or her performance, one who shows improvement (of individuals or groups).
   • 2011, “Stay the Night: The Blackaddie Hotel, Sanquhar,” The Independent, 27 August, 2011,

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

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

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

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

     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.

4. A substance added to cause improvement (especially to a foodstuff).
   • 2016, Wendyl Nissen, “Who kneads so many ingredients?” The New Zealand Herald, 6 August, 2016,

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

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

     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.

5. (historical) A pad worn by women to make the dress hang properly.