What is the difference of a weakly lossy and a loss-less transmission lines?

lossless transmission line , is ideal transmission line with no attenuation , this will make u move in smith chat on a circile , it is ideal element just used in design
but weakly loss i don't know ,
i know lossy , which the loss mechanics is included like meta loss , and dielectric loss

khouly

do you mean low loss transmission line by weakly lossy?