責任 (sekinin) means duty or responsibility. It refers to the state of being accountable for something, or the obligation to deal with something or to control someone. It's about what you should do or what you are blamed for. For example, 'この仕事には大きな責任が伴う。' (This job comes with great responsibility.)

責任 (せきにん) は自分がすべきこと、あるいは結果に対して負う義務。大切な仕事や約束で使います。例：責任を果たす。