Grexit is a portmanteau of 'Greece' and 'exit,' referring to the potential withdrawal of Greece from the eurozone. The term gained prominence during the European debt crisis of 2010-2015 when Greece's sovereign debt problems threatened the stability of the euro.
Example
“In 2015, fears of Grexit intensified when Greece held a referendum on bailout terms, causing EUR/USD to drop sharply as traders priced in the risk of a eurozone breakup.”