Counteract (verb)

1. To act in opposition to (something) in order to reduce or prevent its effects.
2. To neutralize or counteract the effects of (something) by producing an equal and opposite effect.
3. To oppose or counteract the effects of (something) by taking action to reduce or remove them.
4. To take measures to reduce or counteract the effects of (something).
5. To neutralize the effects of (something) by making it less powerful or effective.

Origin:

From the latin contra + actus, meaning 'to act against'.

Examples:

1. He drank coffee to counteract the drowsiness caused by the medicine.
2. The company introduced new policies to counteract the decline in sales.
3. She took steps to counteract the negative effects of stress on her health.
4. The government introduced new laws to counteract the rise in crime.
5. The vitamin supplement was designed to counteract the effects of a poor diet.