Ahead of nothing, about to drive fast (7)
I believe the answer is:
ramadan
'fast' is the definition.
(month of fasting in Islam)
'ahead of nothing about to drive' is the wordplay.
'ahead of' says to put letters next to each other (some letters go in front of others).
'nothing' becomes 'nada' (synonyms).
'about' says the letters should be written in reverse.
'to drive' becomes 'ram' (RAM drive on a computer).
'nada' backwards is 'adan'.
'adan' after 'ram' is 'RAMADAN'.
(Other definitions for ramadan that I've seen before include "The fasting month for Muslims, ninth of year" , "Islamic month (of fasting)" , "lunar month" , "Islam holy month" , "Month in Muslim calendar" .)