vitiate

"The teacher organized a friendly game of basketball after school. "

"My friend told me there was something in the box, but I didn't know what it was yet. "

"His constant negativity at work made it hard for the team to finish projects. "

"The constant noise from the construction site made it hard to concentrate on my homework. "

"The atmosphere was thick with the smell of popcorn, as the kids gathered for the movie night. "

"The family prioritized security by installing a strong lock on the front door. "

"The team was demoralized after losing their tenth game in a row. "

"Go easy on him: he is but a child."

"Everyone in the class needs to bring their textbook to the first lecture. "

"The bug spray was ineffective; the mosquitoes were still biting us. "

"The new evidence invalidated the contract for the house, meaning the buyer no longer had to buy it. "

"The effectiveness of the drug was well established."