WordWeb Online

1. Lacking companions or companionship
   "a lonely fisherman stood on a tuft of gravel";
   - alone, lone, solitary
    
2. Marked by dejection from being alone
   "felt sad and lonely"; "the loneliest night of the week";
   - lonesome
    
3. Characterized by or preferring solitude
   "a lonely existence";
   - lone, solitary
    
4. Devoid of creatures
   "a lonely crossroads";
   - solitary, unfrequented

Derived forms: lonelier, loneliest

See also: dejected, unaccompanied, uninhabited, unsocial

Encyclopedia: Lonely Lonely, Cryin', Only Lonely, Cryin’, Only