The most common and most likely answer to this crossword clue is the 5 letter word RECON
I've seen this crossword clue in The Guardian
R
E
C
O
N
More clues leading to the result RECON
- Military activity, trick by soldiers
- Lag behind army corps, gathering information for the Americans
- An American’s observation of cheat, not for the first time
- Knock a thousand off figure for survey
- Scouting about company with new leader
- US army survey estimate 1000 missing
- Survey characters protected in our economy
Buddy explains!

The straight part
We know that "gathering information for the Americans" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gathering information for the americans = recon.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 RECON mean?
RECON noun- Reconnaissance.
- Reconnoiter.
- The smallest genetic unit that is capable of undergoing recombination.