The most common and most likely answer to this crossword clue is the 7 letter word IFFIEST
I've seen this crossword clue in The Guardian
I
F
F
I
E
S
T
More clues leading to the result IFFIEST
Buddy explains!

The straight part
We know that "dodgy in the extreme" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dodgy in the extreme = iffiest.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 IFFIEST mean?
IFFIEST adjective- Of dubious authenticity, legitimacy or legality.
- Uncertain or chancy.