‘Painterly’ refers to the technique of painting in a loose or less controlled manner, so you can see brush strokes in the final piece.
'Painterliness' is a concept derived from the German term "malerisch" (painterly), introduced by Swiss art historian Heinrich Wölfflin (1864–1945) to standardise the terminology used by art historians in characterising artworks.
The term ‘Painterly’ is used to describe art created in a style that celebrates the specific medium it was made with, such as oil paint, acrylic paint, pastels, or watercolour. Painterly works embrace the texture and movement of the materials, resulting in visible brushstrokes, giving them a more textured and polished appearance. This style is favoured by many artists.
Painterliness is characterised by the application of paint in a loose and less controlled manner, leading to visible brushstrokes in the finished artwork. Prominent art movements associated with painterly styles include Impressionism, Fauvism, and Abstract Expressionism, with Impressionism being one of the most notable examples. Artists like Monet, Renoir, Manet, Degas, and Cézanne, among others, exemplify the painterly style in their works.