Wiktionary
n. (context legal English) The method of interpreting a statute whereby it takes the effect that its originating legislative body intended for it; essentially, enacting the spirit, rather than the letter, of the law.
Wikipedia
The purposive approach (sometimes referred to as purposivism, purposive construction, purposive interpretation, or the "modern principle in construction") is an approach to statutory and constitutional interpretation under which common law courts interpret an enactment (i.e., a statute, part of a statute, or a clause of a constitution) in light of the purpose for which it was enacted.
The historical source of purposive interpretation is the mischief rule established in Heydon's Case. Purposive interpretation was introduced as a form of replacement for the mischief rule, the plain meaning rule and the golden rule to determine cases. Purposive interpretation is exercised when the courts utilize extraneous materials from the pre-enactment phase of legislation, including early drafts, hansards, committee reports, and white papers. The purposive interpretation involves a rejection of the exclusionary rule.
Israeli jurist Aharon Barak views purposive interpretation as a legal construction that combines elements of the subjective and objective. Barak states that the subjective elements include the intention of the author of the text, whereas the objective elements include the intent of the reasonable author and the legal system’s fundamental values.
Critics of purposivism argue it fails to recognize the separation of powers between the legislator and the judiciary. The legislator is responsible for the creating the law, while the judiciary is responsible for interpreting law. As purposive interpretation goes beyond the words within the statute, considerable power is bestowed upon the judges as they look to extraneous materials for aid in interpreting the law.