The most common and most likely answer to this crossword clue is the 7 letter word SYNERGY
I've seen this crossword clue in The Guardian
S
Y
N
E
R
G
Y
More clues leading to the result SYNERGY
- Benefit of merger, say, shedding a work unit in New York
- Offender pronounced extremely guilty offers co-operation
- Working together ultimately jockey often restrained frisky greys
- Adulterer, say, gutless guy in collaboration
- Conspirator against Caesar, we hear, heartless guy in combined action
- Year amongst half-hearted environmentalists brought about end to very co-ordinated action
- Collaboration with offender and my Lord on the radio?
Buddy explains!

The straight part
We know that "collaboration" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case collaboration = synergy.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 SYNERGY mean?
SYNERGY noun- (systems theory) A synonym of binding energy.
- The cooperation of two or more nerves, muscles, organs, etc.
- The combined action of two or more drugs where the effects are stronger than their mere sum.
- Benefits resulting from combining different groups, people, objects or processes.