(slang, derogatory) Someone who attempts to take advantage of a given set of rules, usually by using an overly-literal interpretation that is contrary to their intent, or by selectively choosing which rules take precedence in a given situation.

(politics) Synonym of divide and conquer

(law) A legal doctrine that prevents a murderer from realizing any inheritance from their victim, in effect in most jurisdictions.

plural of slayer rule

(idiomatic, Britain, informal) To be popularly accepted, or supported by the general majority of people.

(sports) A rule regarding play on a specific field, course, or court. / (idiomatic, usually in the plural) The basic rules or standards; whatever someone must know before proceeding.

The laws that govern driving, especially of motorists and cyclists. / (figuratively) A set of standard procedures or regulations governing the way something is done.

A fundamental rule, upon which other matters hinge.

(music) A rule that modifies a well-formed structure (in limited ways). / (grammar) A rule that takes an input and changes it in some restricted way to result in a surface structure.

A general guideline, rather than a strict rule; an approximate measure or means of reckoning based on experience or common knowledge. / (attributive, usually hyphenated) Approximated, guesstimated.