From the given options select the one that rightly explains the given expression:

A snake in the grass

A hidden enemy

The idiom "a snake in the grass" most clearly explains a hidden enemy. The idiom comes from the literal meaning of a snake hiding in the grass, which is a metaphor for someone who is pretending to be friendly but is actually planning to harm you. In the same way, when someone is said to be "a snake in the grass," they are someone who is not who they seem to be and who is secretly plotting against you.

The other options are not as accurate. A jealous person is someone who is envious of someone else's success. A lazy person is someone who is unwilling to work hard. A hungry person is someone who is feeling the need to eat.