A number scoffed loudly (5)
I believe the answer is:
eight
'a number' is the definition.
(I know that eight is a type of digit)
'scoffed loudly' is the wordplay.
'scoffed' becomes 'ate' ('to scoff' is to eat).
'loudly' shows a homophone (sound like) (when spoken - not silently).
'ate' sounds like 'EIGHT'.
(Other definitions for eight that I've seen before include "Where arrogance is needed" , "Several in a row" , "Cube of two" , "Figure" , "Number etched by a skater?" .)