Stainless means not staining or rusting, or without a blemish. Stainless steel, a stainless record, stainless and bright.
Stainless steel resists rust because the chromium in it forms an invisible oxide film that heals itself when scratched — which is why it is not paint and cannot wear off. The figurative sense means morally spotless and is old-fashioned. Note that -less means without, as always.
1adjectivestainlessNot staining or rusting.
“The new kitchen has a stainless steel sink that still looks as good as new.”
stainless is a quality of resisting marks.
Proto-Indo-European
*steyh₂- — to stiffen
Proto-Germanic
*stainaz — stone
gmq-pro
ᛊᛏᚨᛁᚾᚨᛉ
Old Norse
steina — to stain, colour, paint
Middle English
steinen
English
stain
English, today
stainless
Built from
From stain + -less. stain comes from Middle English steinen, steynen (“to stain, colour, paint”), of gmq origin, from Old Norse steina (“to stain, colour, paint”), from steinn (“stone, mineral blue, colour, stain”), from gmq-pro ᛊᛏᚨᛁᚾᚨᛉ, from Proto-Germanic stainaz (“stone”), from Proto-Indo-European steyh₂- (“to stiffen”). Cognate with Old English stān (“stone”). More at stone. Replaced native Middle English wem (“spot, blemish, stain”), from Old English wamm (“spot, stain”). In some senses, influenced by unrelated Middle English disteynen (“to discolor, remove the colour from"; literally, "de-colour”), from Anglo-Norman desteindre (“to remove the colour from, bleach”), from Old French destaindre (“to remove the color from, bleach”), from des- (“dis-, de-, un-”) + teindre (“to dye”), from Latin tingo.
Etymology from Wiktionary, CC BY-SA