Common Words:
* Contraband: Goods that are illegal to import or export.
* Contraceptive: Something that prevents pregnancy.
* Contrary: Opposite or different.
* Contradict: To say or show that something is not true.
* Contrast: To show a difference between two things.
* Contract: A legal agreement.
Less Common Words:
* Contraindication: A reason why something is not advisable or safe.
* Contravene: To go against a rule or law.
* Contralateral: On the opposite side of the body.
* Contrapuntal: Relating to counterpoint in music.
* Contrapositive: A logical statement formed by switching the hypothesis and conclusion and negating both.
* Counterclockwise: Moving in the opposite direction of the hands of a clock.
* Counterproductive: Having the opposite effect to the one intended.
* Counterrevolution: A revolution against a previous revolution.
* Countermand: To cancel a previous order.
This is not an exhaustive list, but it provides a good starting point.
Remember that "contra-" is a Latin prefix meaning "against" or "opposite." This helps to understand the meaning of the words it is attached to.