Shot driven over short extra covers (4)
I believe the answer is:
dose
'shot' is the definition.
(I have seen 'Shot of medicine ' mean 'dose' so perhaps 'shot' could also mean 'dose')
'driven over short extra covers' is the wordplay.
'driven' becomes 'd' (this might be a standard abbreviation I've not previously seen).
'over short' becomes 'o' (cricket abbreviation; 'short' indicates an abbreviation).
'extra' becomes 'spare' (both can mean left over).
'covers' means to remove the middle letters (I've seen 'covering' mean this (the letters which cover the word are used)).
'spare' with its middle taken out is 'se'.
'd'+'o'+'se'='DOSE'
Can you help me to learn more?
(Other definitions for dose that I've seen before include "Medicate" , "Medicinal amount" , "Shot of medicine" , "Measured portion of medicine" , "some Viagra, perhaps?" .)