The most common and most likely answer to this crossword clue is the 4 plus 4 letter word BOOT CAMP
I've seen this crossword clue in The Daily Telegraph
B
O
O
T
C
A
M
P
More clues leading to the result BOOT CAMP
- Centre for juvenile offenders affected by return of further bishop
- Smell round side of lamppost affected where terrier potentially goes
- Affected by kick in a US military training base
- Affected by kick in correctional facility
- Place providing spare site for guys in military centre
- Chelsea perhaps joining party in reform centre
- Sack male in top disciplinary facility
- & 24d Big name in oil, perhaps Aberdonian, too uppity to enter military unit
- Profit affected training centre
- Car’s back by river overlooking quiet military establishment
Buddy explains!
The straight part
We know that "US military training base" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case us military training base = boot camp.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.