The most common and most likely answer to this crossword clue is the 5 letter word CREDO
I've seen this crossword clue in The Times
C
R
E
D
O
More clues leading to the result CREDO
- Choirmaster’s beginning to repeat part of Mass
- Beliefs of left-winger disrupting firm
- Socialist bound by firm principles
- Belief in some sacred order
- Teaching about GOP-style love
- Conservative referring to party’s belief set
- Company absorbing revolutionary statement of belief
- Conservative to reformulate list of basic tenets?
- At first cynical concerning party’s beliefs
- Description of socialism in business doctrine
Buddy explains!

The straight part
We know that "Belief" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case belief = credo.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CREDO mean?
CREDO noun- A belief system.
- The liturgical creed (usually the Nicene Creed), or a musical arrangement of it for use in church services.