Awful girl one cut from quickly (7)
I believe the answer is:
ghastly
'awful' is the definition.
(I've seen this in another clue)
'girl one cut from quickly' is the wordplay.
'girl' becomes 'g'.
'one' becomes 'i' (Roman numeral).
'cut from' suggests deleting specific letters.
'quickly' becomes 'hastily' (done with haste).
'hastily' with 'i' removed is 'hastly'.
'g'+'hastly'='GHASTLY'
(Other definitions for ghastly that I've seen before include "Cadaverous" , "Hideous" , "Very pale" , "Most unpleasant" , "Macabre" .)