Vocab InfoA17 Noun内因(ないいん)actual reasonDetailsExamples内因actual reasonDetailsExamplesDictionary DefinitionNoun1. the actual reasonAll Forms内因 【ないいん】DetailsAudioPlayExamplesThere are no sentences available for this contentHold tight, context sentences are coming soon!Self-Study SentencesStudy your own way!Add sentences and study them alongside Bunpro sentences.Try Bunpro