Digit spreading manure by end of nail (7)
I believe the answer is:
numeral
'digit' is the definition.
(I've seen this in another clue)
'spreading manure by end of nail' is the wordplay.
'spreading' indicates an anagram.
'by' says to put letters next to each other.
'end of' says to take the final letters.
The final letter of 'nail' is 'l'.
'manure' is an anagram of 'numera'.
'numera'+'l'='NUMERAL'
(Other definitions for numeral that I've seen before include "Figure representing an integer" , "Symbol for number" , "Mathematical figure" , "Figure or symbol like '1', for example" , "Figure denoting a number" .)