basic, cardinal, first, fundamental, golden
ground rules
You and your room-mates should establish some ground rules.

general
special
formal, official, written
informal, unspoken, unwritten
old, traditional
the traditional rules of grammar

current, existing
proposed
new
rigid, strict, stringent
absolute, hard and fast
There are no hard and fast rules when it comes to choosing a typeface.

clear
simple
Follow these few simple rules, and you won't go far wrong.

arbitrary
petty (esp. BrE)
He made his children's lives a misery with all his petty rules.

club, company, competition, house, school, union, etc.
federal, global, international
federal rules on campaign fund-raising

cultural, ethical, legal, moral, social
accounting, disciplinary, immigration, privacy (esp. AmE), safety, tax
grammar, grammatical

set
The aim is to get each member country to adhere to a single set of rules.

create, develop, draw up, establish, formulate, impose, issue, lay down, make, set out, write
The rules were drawn up to make it fair for everyone.
You don't make the rules, you know.

abide by, accept, adhere to, follow, go by, obey, observe, play by, stick to
If he wanted a loan he would have to play by the bank's rules.

be in line with, conform to
The packaging does not conform to EU rules.

have
The sport has strict rules for player safety.

be in breach of, break, disregard, fall foul of (BrE), flout, ignore, violate
Their action was in breach of Stock Exchange rules.

apply, enforce
The referee applied the rules to the letter (= very strictly).

adopt, use
bend, relax
Couldn't they just bend the rules and let us in without a ticket?

waive
tighten up
The rules on claiming have been tightened up.

change, rewrite
The Internet has changed the rules of business.
The rules of dating have had to be rewritten, thanks to the movies.

be bound by, be governed by
Employees are bound by rules of confidentiality.

know, learn, remember
You should know the rules by now.

read
explain
interpret, understand
The punishment depends on how the umpire interprets the rules.

apply, be applicable, operate
come into effect, come into force
New accounting rules come into force next year.

dictate sth, provide sth (formal), require sth, say sth, state sth, stipulate sth
The competition rules provide that a cash alternative may be given.

govern sth
the rules governing the importing of livestock

allow sth, allow for sth, permit sth
The existing rules allow for some flexibility.

forbid sth, prevent sth, prohibit sth
limit sth, restrict sth
rules limiting imports

change
The rules keep changing.

book
The officials went strictly by the rule book.

change
Several proposed rule changes have been announced.

according to the rules
According to the rules, no alcohol can be consumed on the premises.

against the rules, contrary to the rules
Tackling a player without the ball is against the rules.

in accordance with the rules
The music was turned off at midnight, in accordance with the rules.

outside the rules
conduct which is outside the rules

under a/the rule
Under this rule, only full members of the club are entitled to vote.

within the rules
I believed I was acting within the rules.

rule about, rule concerning, rule on, rule regarding, rule relating to
What are the school rules about dress?

rule for
There seems to be one rule for the rich and another for the poor.
What is the rule for forming plurals?

rule of
the rules of the game

a breach of the rules, a violation of the rules
a body of rules, a code of rules, a system of rules
respect for the rules
rules and regulations
rule of thumb (= a practical method of doing or measuring sth)

general
There are few exceptions to the general rule that bars close at midnight.

as a rule
As a rule, hardly anybody uses this road.

be the rule
Among her friends, casual dress and a relaxed manner are the rule.

authoritarian, harsh
direct, indirect
emergency
The president imposed emergency rule following the riots.

majority
one-party
Communist, Labour, Republican, etc.
colonial, imperial
home
civilian, military
presidential
constitutional, democratic
mob
the lawless days of mob rule

impose

under … rule
The country remained under direct rule by the occupying powers.

the rule of law
a society based on the rule of law