The most common and most likely answer to this crossword clue is the 6 letter word SETTER
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More clues leading to the result SETTER
Buddy explains!

The straight part
We know that "I" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case i = setter.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 SETTER mean?
SETTER noun- One who sets something, especially a typesetter.
- A long-haired breed of gundog (Wikipedia).
- The player who is responsible for setting, or passing, the ball to teammates for an attack.
- A function used to modify the value of some property of an object, contrasted with the getter.
- (in combinations) A game or match that lasts a certain number of sets.
- One who hunts victims for sharpers.
- One who adapts words to music in composition.
- A shallow seggar for porcelain.
- To cut the dewlap (of a cow or ox), and insert a seton, so as to cause an issue.