Learn how to say Rustless correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word rust:
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
the MPs are here to scrape the rust off the derelict machinery of government
2 [usually with adjective or noun modifier] a fungal disease of plants which results in reddish or brownish patches.
The fungi belong to Puccinia and other genera, order Uredinales, class Teliomycetes
3a reddish-brown colour:
her rust-coloured coat