University visits as yet unscheduled, blow it! (4)
I believe the answer is:
tuba
'university' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for tuba that I've seen before include "Musical instrument -- 5 (rev)" , "Stop" , "Noisy instrument" , "member of band" , "One's blown" .)