The most common and most likely answer to this crossword clue is the 7 letter word FURIOUS
I've seen this crossword clue in The Daily Telegraph
F
U
R
I
O
U
S
More clues leading to the result FURIOUS
- Inquisitive making cold female angry
- Angry? But I love you cutting into expensive coats!
- Incandescent moon with Rufus flailing around
- Fast partner possibly hopping mad
- Hide debts? That’s mad
- Pelt one with donuts, oddly missed, getting angry
- I have a ball and Rufus is running about like mad
- Hopping mad, seeing evidence of debts attached to coat
- Fit to be tied down with debts
- Raging hides evidence of debts
Buddy explains!

The straight part
We know that "Extremely angry" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case extremely angry = furious.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 FURIOUS mean?
FURIOUS adjective- Feeling great anger; raging; violent.
- Rushing with impetuosity; moving with violence.