Pie-eyed guy’s precarious course (9)
I believe the answer is:
tightrope
'precarious course' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'pie-eyed guy's' is the wordplay.
'pie-eyed' becomes 'tight' (I can't explain this - if you can you should believe this answer much more).
'guy' becomes 'rope' (guy is a type of rope or cable).
'tight'+'rope'='TIGHTROPE'
Can you help me to learn more?
(Other definitions for tightrope that I've seen before include "Acrobat's walkway" , "High wire" , "Cable on which acrobatics are performed" , "Entertaining line" , "Difficult thing to walk on" .)