IPA: /ˈrʌstɪə/
KK: /ˈrʌstɪər/
Having more rust than something else; less well-maintained or more corroded.
The old bike was rustier than the new one.
Comparative: rustier
Superlative: rustiest
Rustier → The word 'rustier' is formed from 'rust' (from Old English *rust*, meaning the reddish-brown coating that forms on iron) and the comparative suffix '-ier' (meaning more). Thus, 'rustier' means more rusty or having more rust than something else.
Think of the reddish-brown coating ('rust') that forms on metal, and remember that 'rustier' means having more of that rust.