The crossword solution for the term 'Sink or ___' is 'SWIM' (4 letters). This phrase is often used to describe a situation in which one has two options, either to sink or SWIM. It is usually used to refer to a difficult situation in which one must make a decision and take action in order to survive. The phrase can also be used to refer to a situation in which one must choose between two paths, one of which is more difficult than the other.