Choose the antonym of 'CHILDISH' out of the options given below:

The word "childish" refers to behavior or characteristics that are typical of a child. The antonym "mature" suggests qualities or behavior associated with adulthood, showing a development beyond childlike attributes. Therefore, "mature" is the opposite of "childish" in this context.

• ill-natured: This means bad-tempered or unpleasant, which isn't the opposite of childish.
• sincere: This means honest and genuine, which isn't the opposite of childish.
• converge: This means to come together or meet at a point, which is not related to the concept of maturity or childishness.