rain-slick

The compound adjective "rain-slick" is a modern English formation that transparently combines two elements with ancient Germanic roots. The first element, "rain," descends from the Proto-Germanic regna-, a term for precipitation, which itself has possible Proto-Indo-European connections to a root meaning 'moist.' The second element, "slick," originates from a Germanic base meaning 'smooth' or 'to glide,' related to Old Norse 'slíkr' (sleek) and the concept of slipperiness. The compound's logic is directly descriptive: it denotes a surface whose characteristic slipperiness is specifically caused by the presence of rainwater, evolving from the literal, physical qualities of its components into a fixed collocation often used in descriptive writing, particularly for roads or pavements.

Structure: rain (water falling from clouds) + slick (smooth and slippery) - rain: From Old English regn, of Germanic origin; related to Dutch regen and German Regen. Functions as a noun used attributively to specify the cause or condition. - slick: From Middle English slicke, likely from Old English -slice (as in unslic 'smooth'), related to Old Norse slíkr 'sleek'. Functions as an adjective meaning smooth and slippery.