FADE' (3 letters) The crossword solutions for the term 'become extinct, with 'OUT'' are 'DIE' and 'FADE'. This phrase is used to describe a species or organism that has gone extinct, meaning it is no longer living or existing. Extinction can be caused by natural events such as climate change, or by human activities such as hunting or deforestation. When a species becomes extinct, it is said to have died OUT or faded away.