Precipitous cliff alongside right-hand edge of railway - alarming (5)
I believe the answer is:
scary
'alarming' is the definition.
(similar in meaning)
'precipitous cliff alongside right-hand edge of railway' is the wordplay.
I cannot quite understand how this works, but
'cliff' could be 'scar' (I've seen this before) and 'scar' is found within the answer.
A single letter 'y' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for scary that I've seen before include "[SPICE]" , "spook" , "Hair-raising" , "Alarming, maybe paranormal" , "Frightening or spooky" .)