rust ‧ y /ˈrʌsti/ BrE AmE adjective
1 . metal that is rusty is covered in ↑ rust :
a rusty nail
a new metal that will never go rusty
2 . if you are rusty, you are not as good at something as you used to be, because you have not practised it for a long time:
My French is a bit rusty.