The most common and most likely answer to this crossword clue is the 6 plus 1 letter word INEPT} –
I've seen this crossword clue in The Daily Telegraph
I
N
E
P
T
}
â
€
“
Buddy explains!
The straight part
We know that "Stupid" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case stupid = inept} –.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 INEPT} – mean?
INEPT} – adjective- Not able to do something; not proficient; displaying incompetence.
- Unfit; unsuitable.