You've posted this twice and I wonder whether you were looking for the search box. Is this the full clue (RTE clues are usually very wordy and often convoluted) and what is the letter count and possible pattern please?
The Answer is Agent Green .. maybe there is something wrong with your keyboard submitting the full clue This is no Quentin Tarantino character, but a deadly defoliant from Apocalypse Now 3d and 12 across