Refers to the reddish-brown coating that forms on iron or steel due to oxidation. Can also be used metaphorically for something that has deteriorated or become outdated.
自転車のチェーンに錆が出てきた。
Rust has started to appear on the bicycle chain.
The kitchen knife that hadn't been used for a long time was rusty.
Rust formed on the chain of the old bicycle.
I scrubbed the rust off the tool with a brush.
Applying oil prevents the metal from rusting.
錆 (さび) means literal rust or corrosion on metal, while 寂 (さび) is the aesthetic term for the beauty of age and patina, even though they share the same pronunciation.
iron rust; iron hydroxide
rusty sword; sword with a rusted edge; useless sword
Rarely used kanji form.