It's a jumbo and a minute before noon it flies (7)
I believe the answer is:
mammoth
'it's a jumbo' is the definition.
(thesaurus)
'a minute before noon it flies' is the wordplay.
'a minute' becomes 'm' (abbreviation).
'before noon' becomes 'AM' (as in AM on a clock).
'it flies' becomes 'moth' (I can't explain this - if you can you should give a lot more credence to this answer).
'm'+'am'+'moth'='MAMMOTH'
'and' acts as a link.
Can you help me to learn more?
(Other definitions for mammoth that I've seen before include "Extinct species of elephant" , "Huge" , "Extinct type of elephant" , "Gigantic - extinct animal" , "Prehistoric woolly elephant" .)