Wiktionary
slouchiness
n. The state or condition of being slouchy.
Usage examples of "slouchiness".
Sean was a slender, athletic type, close-cropped blonde hair and a certain slouchiness that betrayed his slacker stature.
That kind of cool slouchiness always impressed Jimmy, coming from another guy: it was the sense of energies being held back, held in reserve for something more important than present company.