Jenny, a Salvation Army girl, in some African lake once? (5)

I believe the answer is:

nyasa

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'girl in some african lake once?' is the definition.
I can't judge whether this definition defines the answer.

'jenny a salvation army' is the wordplay.
'jenny' becomes 'ny' (I can't justify this - if you can you should give a lot more credence to this answer).
'salvation army' becomes 'SA' (abbreviation).
'ny'+'a'+'sa'='NYASA'

Can you help me to learn more?

(Other definitions for nyasa that I've seen before include "Malawi, formerly" , "US city as a" , "lake in Africa" , "Former name of Lake Malawi" .)

I've seen this clue in the Sydney Morning Herald.

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