The most common and most likely answer to this crossword clue is the 9 letter word FREEMASON
I've seen this crossword clue in The Guardian
F
R
E
E
M
A
S
O
N
More clues leading to the result FREEMASON
- Man with secret order to release mother and child
- Secret society member criminal men so fear
- Loose family members one’s seen in lodge
- Identical somersaults nailed by cooler member of brotherhood
- Lodger perhaps presumptuous with mother and child
- Unusual forenames for a lodger?
- Forenames out of place for member of a secret order
- Member of society that’s dispensed with forenames
- One in lodge scrawling forenames
- Society member‘s unusual forenames
Buddy explains!

The straight part
We know that "member of brotherhood" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case member of brotherhood = freemason.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 FREEMASON mean?
FREEMASON noun- A member of a guild of skilled itinerant masons during the Middle Ages and early modern times.