Small group of farmers entering my land, sacking and jeering (8)
I believe the answer is:
scornful
'jeering' is the definition.
'small group of farmers entering my land sacking and' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'group of farmers' becomes 'nfu' (National Farmers' Union).
'entering' is an insertion indicator.
'my' becomes 'cor' (I've seen this in other clues**).
'sacking' is a deletion indicator.
'land' with 'and' taken out is 'l'.
'cor'+'l'='corl'
'nfu' placed inside 'corl' is 'cornful'.
's'+'cornful'='SCORNFUL'
(Other definitions for scornful that I've seen before include "Showing contempt for" , "Openly contemptuous" , "Contemptuous or derisory" , "Disdainful, contemptuous" , "Expressing extreme contempt" .)