The phrase 'Play Hooky' means to skip school, work or any other obligation without a justified excuse.
Example of use: “My friends are playing hooky today so that they can be first in line to buy tickets for the concert tonight”
The origin of the term "hooky" is in the 14th century Dutch game 'hoekje', or as it's known in American culture – 'hide and go seek'. However, the first recorded use of the phrase "playing hooky" was in 1842 in the Brooklyn Daily Eagle: "When I was a child, I thought as a child.... hunted birds' nests, played hooky, and chased butterflies... ". The analogy behind the story is playing games while skipping school.