Can refer to anything that has lost its function or relevance, often used metaphorically.

जो अपनी कार्यक्षमता या प्रासंगिकता खो चुका है

English Usage: After the project failed, it felt like all the ideas we had were just dead matter.

Hindi Usage: जब प्रोजेक्ट विफल हो गया, तो ऐसा लगा कि हमारे पास मौजूद सभी विचार बस मृत पदार्थ हैं.