Lonely is the ache of having nobody around when you want somebody. A Sunday afternoon where the phone does not ring; eating dinner with the television on for the sound of a voice.
Lonely and alone are not the same word, and the gap between them matters. Alone is a fact: you are the only person in the room. Lonely is how you feel about it, and you can be lonely in a crowded office and perfectly content alone on a hillside. The noun is loneliness; lonesome is the American cousin. Lonely also describes places rather than people — a lonely road, a lonely farmhouse on the moor — meaning empty of people, with a hint of unease in it. When you only mean that nobody was with you, say I was on my own, because I was lonely tells people you were unhappy.
1adjectivelonelyUnhappy because you have nobody's company.
“The first winter in the new flat was lonely.”
synonyms: lonesome
2adjectiveplaceOf a place: far from other people, with almost nobody about.
“A lonely farmhouse stood at the end of the track.”
3adjectivespentSpent without company.
“It was a lonely drive back through the rain.”
Too few real examples of this word to estimate which sense is commonest.
Lonely is lone with -ly on the end. By the other account it comes straight from alonely, worn down at the front by fast speech — apheresis, the technical name for a word losing its first syllable. Either way, the missing piece is the a of alone.
From lone + -ly, or from an apheretic shortening of alonely. See lone.
Etymology from Wiktionary, CC BY-SA