The most common and most likely answer to this crossword clue is the 8 letter word TAKEOVER
I've seen this crossword clue in The Sunday Telegraph
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More clues leading to the result TAKEOVER
Buddy explains!

The straight part
We know that "aggressive business deal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case aggressive business deal = takeover.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 TAKEOVER mean?
TAKEOVER noun- The purchase of one company by another; a merger without the formation of a new company, especially where some stakeholders in the purchased company oppose the purchase.
- The acquisition of a public company whose shares are listed on a stock exchange, in contrast to the acquisition of a private company.
- A time or event in which control or authority, especially over a facility is passed from one party to the next.