Ruin — it lies west of here (4)
I believe the answer is:
dash
This clue could be a double definition.
'ruin' is the first definition.
(thesaurus)
'it lies west of here' is the second definition.
The definition suggests a singular noun which matches the answer.
Can you help me to learn more?
(Other definitions for dash that I've seen before include "instrument panel" , "Striking" , "style" , "Splash of colour" , "Hyphen; race" .)