A tight back sofa has its back cushioning built in and upholstered directly onto the frame, rather than using separate loose cushions that can be lifted off and plumped. The seat may still use loose cushions even on a tight back sofa, since the term usually refers to the back specifically.
Tight back construction gives a cleaner, more tailored look and there is no need to plump or straighten the back cushions, which suits a more formal or modern living room. The trade off is that the back cushioning cannot be turned to even out wear the way loose cushions can, so its comfort depends entirely on the quality of the filling used underneath the upholstery. See our sofa styles guide for how this affects a sofa's overall look.
