Verb:

ख़बरदार करना, चेतन करना, आगाह करना, सचेत करना, सजग करना, चेतावनी देना,

warn's Usage Examples:

Then I must warn you.  If I find either of you, I am obligated by rules much older than the Immortal Code to do what I must.

"Ah, dear friend," replied Princess Mary, "I have asked you never to warn me of the humor my father is in.

She agreed it had been prudent to warn her.

Please warn us if that happens.

I've done my part to warn you.

But I feel obliged to warn you anyway.

I came to warn you.

Go up the hill and watch for cars so you can warn anyone before they get to the curve.

Paints that warn of overheating.

I warn you again, step aside.

Synonyms:

caution, previse, discourage, alert, threaten, forewarn, inform, alarm, monish, admonish,

Antonyms:

unaware, lethargic, asleep, unalert, unwary,