“Seamless” may be used in a concrete way to describe a piece of fabric, wood or other object. “Seamless” may also be used in a more abstract fashion, such as “a seamless change of authority,” “a seamless production” or “a seamless movement.” Both the figurative and literal interpretations of "seamless" suggest a sense of perfection or flawlessness.
To use “seamless” as an adverb, simply add -ly to the end to make “seamlessly.” For example, "Today's event went seamlessly." “Seamlessness,” while cumbersome, is the noun form of “seamless.” For example, "The seamlessness with which she moves on the dance floor is simply divine."