Flying saucer (1,1,1)
'flying saucer?' is the definition.
(disc made to 'fly' when thrown)
'saucer?' is the wordplay.
I cannot quite see how this works, but
'saucer?' could be 'disc' (synonyms) and 'disc' is found in the answer.
The remaining letters 'us' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for discus that I've seen before include "Circular object thrown in athletics" , "Sporting projectile" , "Olympic field event" , "Olympic throwing event" , "Athlete's projectile" .)