These essentially refer to tailoring, depending on your physique and how much you like tight, tight, or loose-fitting clothing. Specifically, the reports are: Slim fit meaning A slim fit shirt is an extremely narrow choice, especially for those with a slimmer body shape. If the sleeves are narrowed in addition to the waist, that means extra slim fit.Regular fit This fit, which is essentially the classic breed, is most good for those who prefer a looser, looser fit. Meaning of body fit Body fit or as it is often called body fitted shirts are narrowed in this respect somewhere between Regular and Slim.