The name loafer relates to the action relaxing or loafing around in them. Both derivations are to do with the very relaxed nature of the shoe which is a result of the way they are made.
Loafers are generally lightweight shoes, sometimes of moccasin construction. They often have welted, blake stitched or cemented soles, making them suitable for more formal occasions in black.
The Italian 'sprezzatura' look is heavily dependent upon the loafer to finish off the casual but intricate styling, often without socks. Alternatively the 'preppy' look uses the 'penny' loafer style to create a more formal. You can even use them for formal occasions with alittle care - but only in black!.