Leaving aside the whole viking being a job thing, and possibly a quite narrow time period, you are more likely to fall foul of the nordic vs Scandinavian distinction, and if you want to get historical then the rabbit hole goes deeper still (Normans, the Germanics -- Wotan is the German equivalent of Odin in much the same way Greek and Roman gods are the same by different names and few would call any of the Germany tribes/proto regions vikings even if technically some would be* -- Germany is actually younger than the US by almost any way you care to slice it. Add in Russia during all this and it gets even more fun.).
*historical position of the angles, the saxons and the jutes if you want something to look up. That or read about Hengist and Horsa (arguably several centuries before the viking age but also noted in the Prose Edda and doing what would be recognised as such so who knows)..
The rough equivalent would probably be going round calling Americans yankees (nobody likely to care too much about the north-south distinction there). Which is to say most people amused at best but generally indifferent, a few historical pedants and a few would rather commit sudoku than ever offend someone.
Call someone a viking and they will probably take it as a comment on their build, style of dress, hair style and attitude, or if they are from there then a very informal shorthand for that part of the world.