Alone – Lonely – Lonesome
Alone (adjective and adverb) means that no other person is with you. When we use alone as an adjective, it never comes before the noun (predicative adjective):
Lonely (adjective) means that no other person is with you and, as a consequence, you are sad and unhappy. We may choose to be alone but generally we do not choose to be lonely:
Lonesome (adjective), in American English, is the same as lonely. Sometimes it refers to a person in a profound, long-lasting, philosophical, or hopeless way. The difference can be really subtle (if there is one).
–>> People who are alone and solitary are not necessarily lonely or lonesome.
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Loneliness is the feeling of sadness or anxiety that occurs when you are alone and feel depressed about it , The lack of connection or communication may be felt even when surrounded by other people
The loneliness of Eleanor Rigby, which is existential, is unlike the sentimental solitude deriving from a breakup, such as the feeling described in Are you Lonesome Tonight?