http://www.dict.cc/deutsch-englisch/uneingeschränktes Ermess...

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Note added at 8 mins (2015-02-02 20:54:08 GMT)
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The EN should read 'absolute discretion'.

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Note added at 16 mins (2015-02-02 21:02:06 GMT)
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Not 'in' but 'at': at their absolute discretion

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Note added at 39 mins (2015-02-02 21:24:22 GMT)
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Not power, but discretion.
Canadian, eh? Sure he wasn't from Montreal?

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Note added at 51 mins (2015-02-02 21:36:14 GMT)
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Re 'uncontrolled':
This sounds like non-native use. It suggests 'out of control', 'running wild' - inappropriate for a will. Maybe the lawyer was using it in the faux ami sense of 'unmonitored/unsupervised'?

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Note added at 2 hrs (2015-02-02 22:56:24 GMT)
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FRENCH
contrôler (kɔ̃tʀole Pronunciation for contrôler )
(= vérifier) to check ⇒ Personne n'a contrôlé mon billet. Nobody checked my ticket.
(= surveiller) to supervise, to monitor
http://www.collinsdictionary.com/dictionary/french-english/c...

GERMAN
kontrollieren
supervising
checking
check [tech.]
verification - of a survey, calculation, etc. [tech.]
http://dict.leo.org/#/search=kontrollieren&searchLoc=0&resul...

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Note added at 5 hrs (2015-02-03 02:39:39 GMT)
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Well, it turns out that your quoted phrase may indeed be standard for Canada:
"The deceased died in 2000 and left a will which stated in clause 3(A) - "my said trustee may in their uncontrolled discretion decide upon, or to postpone such conversion of my estate or any part or parts thereof for such length of time as they may think best"

http://disinherited.com/court-refuses-order-sale-property-11...

Still sounds weird from this side of the Atlantic. This same link then goes on to quote another will with similar wording: "To sell, call in and convert into money all of my personal estate at such time and in such manner and upon such terms as my Trustees at their absolute discretion determine, with power to them to postpone such conversion…"