The most common and most likely answer to this crossword clue is the 8 letter word INFANTRY
I've seen this crossword clue in The Times
I
N
F
A
N
T
R
Y
More clues leading to the result INFANTRY
- In cooler, test soldiers
- Grunts of young one on the line
- Child runs with unknown soldiers
- Troops recently formed line
- Fighters batting, cool test
- In rugby score keen devoteeās breaking foot
- Child given small railway and soldiers
- Grunts in attempt to keep cool
- Keeping cooler, cool topless soldiers
- Supporter fills in test for part of the army
Buddy explains!

The straight part
We know that "Grunts" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case grunts = infantry.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 INFANTRY mean?
INFANTRY noun- Soldiers who fight on foot (on land), as opposed to cavalry and other mounted units, regardless of external transport (e.g. airborne).
- The part of an army consisting of infantry soldiers, especially opposed to mounted and technical troops
- A regiment of infantry