See a girl disheartened and isolated (6)

I believe the answer is:

lonely

'isolated' is the definition.
(thesaurus)

I cannot understand how the remainder of the clue works.

(Other definitions for lonely that I've seen before include "without friends" , "... in need of company ..." , "Without companions" , "Unfrequented" , "Remote" .)

I've seen this clue in The Times.

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