US army stuff (5,4)
I believe the answer is:
olive drab
'us army' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'stuff' is the wordplay.
I cannot quite see how this works, but
'stuff' could be 'olive' (olive is a kind of stuff) and 'olive' is found within the answer.
The remaining letters 'drab' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for olive drab that I've seen before include "Green colour" , "Greyish" , "Dull colour" , "Military uniform colour" , "a shade unsparkling, maybe" .)