Rusty means coated in the orange-brown crust that forms where iron has met air and water. A rusty gate, rusty nails, the car is rusty underneath.
Only iron and steel rust; other metals corrode differently and are not called rusty. The figurative sense is at least as common: a skill you have not practised is rusty — my French is very rusty, a bit rusty at this. It carries no shame, only disuse. Note rust as both the substance and the verb, rustproof, and rust belt, the American term for a region of declined heavy industry.
1adjectiverustyCoated in the orange-brown crust formed on iron.
“The hinges were rusty and the gate had not opened in years.”
2adjectivepracticeOut of practice.
“My Spanish is rusty but it comes back after a day.”
Too few real examples of this word to estimate which sense is commonest.
rusty is a state of corrosion or disuse.
Old English rustig comes from the same root as red — the colour named the substance. Russet and rust are relatives, and all three descend from a Proto-Indo-European word for red that also gives Latin ruber.
Proto-Germanic
*rustagaz — rusty
Old English
rūstiġ — rusty
Middle English
rusty
English, today
rusty
From Middle English rusty, from Old English rūstiġ (“rusty”), from Proto-Germanic rustagaz (“rusty”), equivalent to rust + -y. Cognate with stq rusterch (“rusty”), West Frisian rustich, roastich (“rusty”), Dutch roestig (“rusty”), German Low German rusterig, rüsterig (“rusty”), German rostig (“rusty”), Swedish rostig (“rusty”).
Etymology from Wiktionary, CC BY-SA