The most common and most likely answer to this crossword clue is the 6 letter word IDIOTS
I've seen this crossword clue in Financial Times
I
D
I
O
T
S
More clues leading to the result IDIOTS
- Island's housing inspector books those behaving stupidly
- Do PE? Go on, without a break!
- Fools do, and it is silly
- Stupid people do it after change of heart, interrupting lives
- Silly people do and it is ridiculous
- Dictator books small chumps
- Poor do. Is it they who are responsible?
- Fools one spots traversing island
- Openings for insane, dumb, inane or totally silly asses
- Fools use jargons, time to replace many
Buddy explains!

The straight part
We know that "Do PE? Go on" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case do pe? go on = idiots.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 IDIOTS mean?
IDIOTS noun- A person of low general intelligence.
- A person who makes stupid decisions; a fool.
- A person of the lowest intellectual standing, a person who lacks the capacity to develop beyond the mental age of a normal four-year-old; a person with an IQ below 30.