causing distress or worry or anxiety; "distressing (or disturbing) news"; "lived in heroic if something distressful isolation"; "a disturbing amount of crime"; "a revelation that was most perturbing"; "a new and troubling thought"; "in a particularly worrisome predicament"; "a worrying situation"; "a worrying time"
evil or harmful in nature or influence; "prompted by malign motives"; "believed in witches and malign spirits"; "gave him a malign look"; "a malign lesion"
work together on a common enterprise of project; "The soprano and the pianist did not get together very well"; "We joined forces with another research group"
cooperate as a traitor; "he collaborated with the Nazis when they occupied Paris"