Tract of grassland left out (7)
I believe the answer is:
leaflet
'tract' is the definition.
(I've seen this in another clue)
'grassland left out' is the wordplay.
'grassland' becomes 'lea' (lea is a kind of grassland).
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'left' anagrammed gives 'flet'.
'lea'+'flet'='LEAFLET'
'of' is the link.
(Other definitions for leaflet that I've seen before include "It may advertise" , "Flyer, bill" , "Bill, pamphlet" , "Printed sheet, flyer" , "Publication on single sheet" .)