The most common and most likely answer to this crossword clue is the 4 plus 2 letter word EVER SO
E
V
E
R
S
O
More clues leading to the result EVER SO
- A first for Ellen Page, really
- Damned English pages left!
- Very eager to start next page after turning
- Incredibly wayward serve gets over
- Clever? Solomon? To some extent? To a huge extent!
- Remarkably English, one side of literature?
- Very, very sore unfortunately after ending on backside
- Really, it is always thus
- Very strange verse on love
- Very moving verse heading start of obituary
Buddy explains!

The straight part
We know that "To a huge extent!" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case to a huge extent! = ever so.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.