The most common and most likely answer to this crossword clue is the 7 letter word SEMINAL
I've seen this crossword clue in The Times
S
E
M
I
N
A
L
More clues leading to the result SEMINAL
- Very important if dropped from cup tie?
- Influential man lies disgracefully
- Ground-breaking tutorial cut short by head of Latin
- Important if knocked out of cup game
- The French city near Montpellier, turning influential
- Influential group of students changing sides
- Ground-breaking if dropped from cup-tie
- Note French city, rising to be influential
- Influential and revolutionary style of animation penned by Lowry?
- It is important to change lanes when encircling motorway
Buddy explains!

The straight part
We know that "Very important" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case very important = seminal.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 SEMINAL mean?
SEMINAL noun- A seed.
- Of or relating to seed or semen.
- Creative or having the power to originate.
- Highly influential, especially in some original way, and providing a basis for future development or research.