A colour with very little hue strength — greys, off-whites, beiges and similar low-saturation colours.
Colourwise classifies a colour as neutral when its HSV saturation falls below a documented threshold, regardless of hue angle.
'Neutral' doesn't mean 'no undertone' — most neutrals still lean warm or cool.
Greige, oatmeal and charcoal are all neutrals.
Neutrals are the most common base colour for walls, flooring and large furniture precisely because they pair with almost everything.