WANTON

Option D is the correct answer,

'Wanton' means reckless, unrestrained, or senselessly excessive, often used to describe cruelty, destruction, or behaviour lacking discipline.

Option D) 'Discreet' means careful, cautious, or showing good judgment, which is the opposite of wanton behaviour.

Option A: Sportive means playful or lighthearted, which is not exactly the opposite of 'wanton.'
Option B: Ardent means passionate or enthusiastic, which is unrelated.
Option C: Fragile means delicate or easily broken, which is not the opposite of 'wanton'