Antonym of “recalcitrant” is:

An antonym is a word opposite in meaning to another. The word "recalcitrant" describes someone who is stubbornly uncooperative, defiant of authority, or resistant to control. It implies a strong unwillingness to comply or obey.

• The correct antonym is Obedient, which means complying or willing to comply with an order or request; submissive to authority. This directly contrasts with the defiance and resistance inherent in being recalcitrant.
• Stubborn is a synonym or very close in meaning to "recalcitrant," as recalcitrance is characterized by stubbornness.
• Rebellious is also a synonym, describing someone who resists authority or control.
• Defiant is another synonym, meaning openly resistant or disobedient. All these distractors describe aspects of recalcitrance rather than its opposite.