PUP.Optional.Wajam is the detection name for Wajam, a browser add-on marketed as a “social search.”
This is the detection for potentially unwanted browser hijackers that use browser extensions to show advertisements.
This potentially unwanted software comes bundled with other software.
Malwarebytes can remove this potentially unwanted program (PUP), but this may require some user interaction.
Example with extra instructions: Removal guide for Tables