Ordered gravel -- not very big (5)
I believe the answer is:
large
'big' is the definition.
(synonyms)
'ordered gravel not very' is the wordplay.
'ordered' indicates anagramming the letters.
'not' suggests deleting specific letters.
'very' becomes 'v' (abbreviation).
'gravel' with 'v' removed is 'grael'.
'grael' with letters rearranged gives 'LARGE'.
(Other definitions for large that I've seen before include "Comprehensive" , "Big, great" , "Above average in size, number, etc." , "Of considerable size or extent" , "Bumper" .)