Crossword Genius

So, to free her, let loose (9)

Ross

I believe the answer is:

therefore

'so' is the definition.
(I've seen this before)

'to free her let loose' is the wordplay.
'let loose' indicates anagramming the letters.
'to'+'free'+'her'='tofreeher'
'tofreeher' anagrammed gives 'THEREFORE'.

(Other definitions for therefore that I've seen before include "Consequently - for that reason" , "has a triangular formation in maths?" , "It follows" , "Thus" , "Ergo" .)

I've seen this clue in The Telegraph.
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