col ‧ lab ‧ o ‧ ra ‧ tor /kəˈlæbəreɪtə $ -ər/ BrE AmE noun [countable]
1 . someone who helps their country’s enemies, for example by giving them information, when the enemy has taken control of their country ⇨ collaborate , collaboration :
Their job was to identify enemy collaborators.
2 . someone who works with other people or groups in order to achieve something, especially in science or art ⇨ collaborate , collaboration :
collaborators on a biography of Dickens