rust
Pronunciation: /rʌst/
noun
- 1a reddish- or yellowish-brown flaking coating of iron oxide that is formed on iron or steel by oxidation, especially in the presence of moisture: paint protects your car from rust figurative the MPs are here to scrape the rust off the derelict machinery of government
verb

Origin:
Old English rūst, of Germanic origin; related to Dutch roest, German Rost, also to red