Infidelamsterdam Share definition Flag Used to describe a sophisticated metalhead that respects other people. The founder is Infidelamsterdam from Youtube; subscribe to him. 1) He's so smart, he's an Infidelamsterdam!2) Infidelamsterdam is smarter than the dalai lama Infidelamsterdam by Cr3scendo December 23, 2010 Get the Infidelamsterdam mug.