Cow neatherd almost forced onto back of cart (8)
I believe the answer is:
threaten
'cow' is the definition.
(I've seen this before)
'neatherd almost forced onto back of cart' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'forced' is an anagram indicator.
'onto' says to put letters next to each other.
'back of' says to take the final letters.
The final letter of 'cart' is 't'.
'neatherd' with its last letter taken off is 'neather'.
'neather' anagrammed gives 'hreaten'.
'hreaten' put after 't' is 'THREATEN'.
(Other definitions for threaten that I've seen before include "Utter intentions of injury or punishment" , "Look likely to" , "indicate danger" , "Bully" , "Menace, warn of intention to harm" .)