From the given options, select the one which is similar in meaning to the given word

"Listless"

Lethargic

The word that is most similar in meaning to "listless" is lethargic.

• Listless means lacking energy or enthusiasm; apathetic.
• Lethargic means lacking energy or vitality; sluggish.

The other options have different meanings.

• Lively means full of energy and life; animated.
• Brisk means moving or operating quickly and energetically.
• Enthusiastic means showing or feeling strong excitement and interest.

So, the answer is Option 3: Lethargic.