1) an official who works in a government department, especially who obeys the rules without exercising much judgment (bureaucrat)

2) a set of laws or rules (code)

3) a system of moral principles, rules of behaviour (ethic)

4) the rules for formal behaviour among people or a profession (etiquette)

5) acting in a just and honest way; in accordance with justice or the rules (of a game etc) (fair)

6) an action required by custom or rules (formality)

7) (of a person) not in the power of another person; not in prison; not controlled or restricted by rules and regulations (free)

8) (the scientific study of) rules for the combination of words into sentences (called syntax), and the forms of words (called morphology) (grammar)

9) of, conforming to, the rules of grammar (grammatical)

10) the science of, rules for, clean and healthy living (hygiene)