The most common and most likely answer to this crossword clue is the 10 letter word HEADBANGER
I've seen this crossword clue in The Guardian
H
E
A
D
B
A
N
G
E
R
More clues leading to the result HEADBANGER
Buddy explains!
The straight part
We know that "one nodding furiously?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one nodding furiously? = headbanger.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 HEADBANGER mean?
HEADBANGER noun- One who dances by violently shaking the head in time to the music.
- (by extension) One who enjoys heavy metal (rock) music, to which this sort of dance is usually performed.
- A mad or eccentric person.
- A kind of chin-up or pull-up exercise where the head is kept in line with the bar.