NOT ON YOUR NELLY Meaning of NOT ON YOUR NELLY in English Brit.certainly not. [orig. as not on your Nelly Duff , rhyming sl. for 'puff' (i.e. breath of life); modelled on the phr. not on your life .] → nelly Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004