One taking inappropriate interest in single nurse we’re told (4,5)

I believe the answer is:

loan shark

'one taking inappropriate interest' is the definition.
(moneylender charging too much interest)

I don't understand how the rest of the clue works.

(Other definitions for loan shark that I've seen before include "Financial dealer" , "Money lender" , "Unscrupulous moneylender (colloq.)" , "One lends money at excessive rates of interest" , "Usurer" .)

I've seen this clue in The Times.

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