The most common and most likely answer to this crossword clue is the 10 letter word REGIMENTAL
I've seen this crossword clue in The Times
R
E
G
I
M
E
N
T
A
L
More clues leading to the result REGIMENTAL
- Like an army unit get manlier when freshly deployed
- Germaine screwed around with short lieutenant of the colonel’s command
- Kray, with terrible ailment relating to military manouevres
- Concerned with soldier, intellectual, from a group of soldiers
- Army unit’s American soldier joining this person in charge
- As part of the army, about to tear ligament
- Get marine redeployed on left of colonel’s men
Buddy explains!

The straight part
We know that "Like an army unit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case like an army unit = regimental.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 REGIMENTAL mean?
REGIMENTAL adjective- Relating to a regiment
- Overly strict; rigid