5 down
Unusually
large
one,
drone
a
US
hit
(9)
Unusually large one, drone a US hit (9)
hints
0
checks
0
hints
The definition is at the beginning of the clue.
How the clue works
See Unusually large one — that's your definition, something truly remarkable or extraordinary. For the wordplay, just stick together HUM (that's your drone) and DINGER (US slang for a hit, like a home run smacked out of the park), and the two pieces slot together to spell it out.