What is Actio Stricti Juris?

Legal Definition
An action of strict right. The class of civil law personal actions, which were adjudged only by the strict law, and in which the judge was limited to the precise language of the formula, and had no discretionary power to regard the bona fides of the transaction. See Inst. 4, 6, 28; Gaius, iii. 137; Mackeld. Rom. Law, ยง 210.
-- Black's Law Dictionary
Legal Definition
An action in which the court followed the letter of the law.
-- Ballentine's Law Dictionary