The state of being alone; solitude, isolation.(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "aloneness" in a sentence
"You should not be without a greeting from me at Christmastime, when in the midst of the festivities your feeling of aloneness is apt to weigh more heavily upon you."
"Recognizing this aloneness is essential for togetherness."
"It was a different kind of aloneness than the kind he had faced in the City, where he'd been surrounded by people every waking moment, and his constant quest had been for privacy."