1. single, solitary; unaccompanied, unattended. Alone, lone, lonely, lonesome all imply being without companionship or association. Alone is colorless unless reinforced by all; it then suggests solitariness or desolation: alone in the house; all alone on an island. Lone is somewhat poetic or is intended humorously: a lone sentinel. Lonely implies a sad or disquieting feeling of isolation. Lonesome connotes emotion, a longing for companionship.