solitariness

The fact or state of being solitary, or alone, or without mate, partner, or companion, or of dwelling apart from others or by one’s self; habitual retirement; solitude.

The state or character of being retired or unfrequented; solitude; seclusion: as, the solitariness of a wood.

Condition of being solitary.

The state or quality of being solitary.

the state of being alone in solitary isolation

a disposition toward being alone