The most common and most likely answer to this crossword clue is the 3 plus 4 letter word IWO JIMA
I
W
O
J
I
M
A
More clues leading to the result IWO JIMA
- Island man in Iowa converted
- Without James I at the front, a fierce battle
- James in Iowa recreated World War II battle
- Battleground has James in a state, turning over inside
- Primarily, it’s where old Japanese infantry met Americans?
- Young lad in a state, stomach turning
- Single woman mostly maintains journal on one WW2 battle
- Primarily it was one job in many as WWII operation
- James in Iowa recreated Japanese island
- 16d
Buddy explains!

The straight part
We know that "Island" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case island = iwo jima.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.