run the risk of rust out?

[bartholomew]

Without challenges at work you run the risk of rusk out, in which you get bored and start clock-watching.

 

what does a rust out mean?

[woofgang]

rusting to bits ie stuck in a corner, never used and never cared for

[jno]

I'm sure woofgang is right (she usually is) - but I might add that I've never heard this phrase before; it may have been made up by the writer you're reading, bartholomew, perhaps in America The usual phrase would be 'you run the risk of getting rusty'.

[woofgang]

There is a saying that I have heard that it is better to wear out than rust out...not sure of origin