ADJ

basic, broad, central, fundamental, general
the basic principles of car maintenance
cardinal, essential, key
universal
democratic, legal, market, political, scientific, theoretical

VERB + PRINCIPLE

establish, formulate, lay down
apply
explain

PRINCIPLE + VERB

apply
This principle applies to all kinds of selling
underlie sth, underpin sth
the principles underlying Western philosophy

PREP

in ~
I agree with you in principle, but we'll need to discuss the details
~ behind
She went on to explain the principles behind what she was doing

ADJ

high
guiding
Christian
moral
He was a man of high moral principles

VERB + PRINCIPLE

betray, compromise
I refuse to compromise my principles by eating meat
adhere to, stick to
She sticks to the principle that everyone should be treated equally

PREP

against your ~s
Eating meat was against her principles
on ~
She's opposed to abortion on principle

PHRASES

a matter of principle
They reject the proposal as a matter of principle
a person of principle (= a person with high moral standards)