like a greased pig

Difficult to catch or hold due to being evasive in some way. Likened to a contest in which contestants attempt to catch a pig that has been covered in grease and set loose. These corporate executives are always like greased pigs when you try to hold them accountable for their actions. I tried to grab hold of our son to bring him inside for dinner, but he was like a greased pig!

like a greased pig

mainly AMERICAN

If someone is like a greased pig, they move very fast and nobody can catch them or stop them. He slid past her like a greased pig. Note: This may come from a fairground competition which was popular in the past, in which a piglet that had been covered in grease was let loose and the person who caught it won a prize.