uberrima fides

from Bouvier's Law Dictionary, Revised 6th Ed (1856)
UBERRIMA FIDES. Perfect good faith; abundant good faith. 
     2. This phrase is used to express that a contract must be made in 
perfect good faith, concealing nothing; as in the case of insurance, the 
insured must observe the most perfect good faith towards the insurer. 1 
Story, Eq. Jur. Sec. 317; 3 Kent, Com. 283, 4th ed. 
    

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