Save the endangered words! The language would be poorer without mansuetude, vilipend, embrangle and skirr.
What you can do: adopt an endangered word and use it frequently.
Such words sometimes represent the archaeology of language - describing forgotten practices, jobs, sounds, smells and states of mind, like accidie. It would be a shame if they were lost.
Hat-tip to the Silver Eel.
Also, if you want to increase your word-power and help feed people, Free Rice is quite fun.