[quote=Assallya]
What does mutant mean in this context? When I see "mutant" I think massively deformed, usually with loose hanging flaps of skin and altogether f-ugly.
[/quote]

Can be that... I'm writing lore right now, but here's the gist (I suck at explaining things):
A mutant is your average non-robotic Wastelander. No two mutants look the same, one could have gills and feathers while another could have 16 eyes and fire breath.