lonesome (adj.)

"drearily solitary; secluded from society; dejected from want of company," 1640s, from lone (adj.) + -some (1). Related: Lonesomeness. An older adjective was loneful (1560s).

Loneliness expresses the uncomfortable feelings, the longing for society, of one who is alone. Lonesomeness may be a lighter kind of loneliness, especially a feeling less spiritual than physical, growing out of the animal instinct for society and the desire of protection, the consciousness of being alone .... Lonesomeness, more often than loneliness, may express the impression made upon the observer. [Century Dictionary]

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Definitions of lonesome from WordNet

lonesome (adj.)
being the only one; single and isolated from others;
a lonesome pine
Synonyms: lone / only / sole / solitary
lonesome (adj.)
marked by dejection from being alone;
spent a lonesome hour in the bar
lonesome when her husband is away
Synonyms: lonely