The most common and most likely answer to this crossword clue is the 5 letter word MACHO
I've seen this crossword clue in Financial Times
M
A
C
H
O
More clues leading to the result MACHO
- Overly masculine Scottish fellow with small house
- Virile army doctor ringing a key hospital
- Aggressively masculine revolutionary embraces church
- He-man Chinese leader keeps in check
- Butch old lady seen at church by Oscar
- Still on a plane? That’s very masculine!
- Very aggressive companion restrained by chairman
- Butch Cassidy’s first house south of Massachusetts
- Swaggering male set up Soho scams without clothes
- Red-blooded pilot’s speed approaching sound barrier?
Buddy explains!

The straight part
We know that "Butch" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case butch = macho.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 MACHO mean?
MACHO noun- A macho person; a person who tends to display masculine characteristics, such as domineering, fierceness, and bravado.
- The striped mullet of California (Mugil cephalus, syn. Mugil mexicanus).
- A male llama.
- Tending to display masculine characteristics, such as domineering, fierceness, bravado, etc., in ways that are showily and histrionically tough