Question

i warned him _____ her treachery​

Answer 1

I warned him against her treachery​.

What is a preposition?

• A preposition is a word that is used before a noun or a noun phrase.
• It is used to indicate the place, time, and direction of an object, person, or place.
• Let's take this, for example, He went into the garden.
• Here 'into' is a preposition.
• Other examples are to, of, in, at, into, and under.

Thus, the correct preposition is 'against'.

Answer 2

Answer: Against

Explanation: