ambush - To suddenly attack someone after hiding and waiting for them:
The brigade walked quietly to the hidden spot on the hill, patiently until the enemy walked in the valley below, so that they could ambush the unsuspecting enemy, who were taken by surprise.
simmer - To heat a liquid, usually a stew or soup, just below the boiling point, allowing it to cook slowly; or to stay in a slow, controlled state of progress or tension, often before a larger event or change occurs.
He was simmering with anger, but he kept it inside and didn't say out loud what he was thinking and feeling.
