An informer providing substantial quantities of information on criminal or terrorist activities to the police.(noun)
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Use "supergrass" in a sentence
"Anderson has been named by a "supergrass" convicted of conspiracy to murder who will give evidence next week. marcpen: A supergrass is a high level ex-gang member who 'turns Queen's Evidence' to become a prosecution witness."
"The case is based around so-called supergrass evidence supplied by Newtownabbey brothers David Stewart (38) and Robert Stewart"
"What are your views of the reports that Mohammed Siddique Khan met Mohammed Junaid Babar the key 'supergrass' prosecution witness in the current 'Operation Crevice' trial ?"