Definition of sliding:
deteriorating (part of speech: verb)
- going downhill,
- getting worse,
- falling apart,
- descending (part of speech: verb)
- "The Boy Aviators' Flight for a Fortune", Wilbur Lawton.
- "The Go Ahead Boys on Smugglers' Island", Ross Kay.
- "The So-called Human Race", Bert Leston Taylor.