boon companion
From Longman Dictionary of Contemporary Englishboon companionˌboon comˈpanion noun [countable] literaryFRIEND a very close friendExamples from the Corpusboon companion• She hadn't deserved their kindness, their good wishes - she'd hardly been a boon companion of late.Origin boon companion (1500-1600) Old French bon; → BONNY