The most common and most likely answer to this crossword clue is the 2 plus 5 letter word SO THERE
I've seen this crossword clue in The Times
S
O
T
H
E
R
E
More clues leading to the result SO THERE
- Defiant remark made by heavy drinker in this place
- Drunkard present, whether you like it or not
- Upset about article? Don't doubt it!
- It’s different in the south-east — I told you so
- Defiant words, likewise, at that place
- Sneering expression at this point on drunk
- Triumphant expression from drunk in this place?
- Defiant remark: it follows comforting one
- Take that drunkard to this location
- Defiant remark from habitual drunkard present
Buddy explains!

The straight part
We know that "I defy you" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case i defy you = so there.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.