"I am thirsty."

Translation: मैं प्यासी हूँ।

[vg]

Why not "मैं प्यासा हूँ।"

[emrys29]

Both are correct.

[ParthChopra]

Your sentence is appropriate if you're male. However the given sentence is for a female speaker. Duolingo should be more specific here.

[shrikrishna1]

How can you say ' The speaker of I am thirsty is a female' ? Translation from English to Hindi!

[arushkotta]

You are correct sir

[raypab]

it is obvious that the word pyaSI is feminine...
NOT ALL but most words in hindi that end with the SOUND of "e" are feminine...