Choose the word that is opposite in meaning to the given word.

Abandon

Constraint

The word that is opposite in meaning to abandon is constraint.

• Abandon means to give up or leave something or someone.
• Constraint means a restriction or limitation on something.

So, the opposite of abandoning something would be to put constraints on it, or to restrict it in some way.

The other words do not have opposite meanings to abandon.

• Recklessness means a lack of caution or care.
• Casualness means a lack of seriousness or formality.
• Spontaneity means the quality of being done without planning or forethought.