تعريف fall off the back of a lorry في الإنجليزية الإنجليزية القاموس.
Of an item of merchandise, to come into a perons's possession without having been paid for; to have been acquired illegally
(British Slang) appear from out of nowhere (ironic expression used to indicate that something came into one's possession in an illegitimate manner, i.e. by theft)