Other contributors have said "How do you use adversary in a sentences?" is the same question as "How can you use the word adversary in a sentence?". If you believe that these are not asking the same thing and should be answered differently, click here.
How can you use the word adversary in a sentence?
Answer:
That castle seemed like it was an adversary, even though it was very old.
Another answer:
The warrior looked like an adversary, because he wore armour, a helmet and carried a sword. John knew the adversary was an enemy by the way he dressed.