Oxford Dictionary English boon companion nounnoun BrE BrE//ˌbuːn kəmˈpæniən// ; NAmE NAmE//ˌbuːn kəmˈpæniən// (literary) Add to my wordlistjump to other resultsa very good friend Word Originmid 16th cent.: boon from Old French bon, from Latin bonus ‘good’. The early literal sense was ‘good fellow’, originally denoting a drinking companion.See boon companion in the Oxford Advanced American DictionaryCheck pronunciation: boon companion oxfordlearnersdictionaries.com