The most common and most likely answer to this crossword clue is the 7 letter word VITALLY
V
I
T
A
L
L
Y
Buddy explains!
The straight part
We know that "in an important way" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in an important way = vitally.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 VITALLY mean?
VITALLY adverb- In a manner that imparts vitality
- To an extent that is vital; indispensably