Definition of "unbeknown"

Following the debate in question, Tim Loughton sent an unmarked copy of Hansard to his constituent to inform him that he would no longer be acting as his MP as the constituent had made this position untenable. [...] However, and unbeknown to Loughton, the constituent reported the debate to the police as a 'hate crime' and complained that sending a copy of Hansard was 'harassment'.

2015, Roger Williams, “Harassment in Sussex”, in Rough Justice: Citizens’ Experience of Mistreatment and Injustice in the Early Stages of Law Enforcement, Hook, Hampshire: Waterside Press, part 1 (Contributions, Media and Experiences), page 106