sly Pronunciation: /slaɪ/Translate sly | into French | into Italian | into Spanish German translation of slyA. adj. schlau; gerissen (ugs.) [Geschäftsmann, Trick]; verschlagen [Blick]B. n. on the sly = heimlichsly in other Oxford dictionaries Definition of sly in the British & World English dictionary Definition of sly in the US English dictionary