patient
A person who stays calm while waiting or dealing with problems.
A patient person can wait calmly without getting frustrated or angry. When you're standing in a long line at an amusement park, being patient means you don't complain every thirty seconds or push ahead. When you're learning something difficult like playing the violin or solving complex math problems, patience helps you stick with it through the awkward early stages when nothing sounds quite right or makes sense yet.
Patience matters because worthwhile things usually take time. A farmer needs patience to wait months for crops to grow. A scientist needs patience to run experiments that might fail dozens of times before succeeding.
The opposite of patient is impatient: someone who gets irritated by waiting, who wants results immediately, who gives up when success doesn't come quickly.
The word also means a person receiving medical care. When you visit a doctor or hospital, you become that doctor's patient. Doctors see many patients each day, examining them and helping them recover from illness or injury. The medical meaning connects to the waiting meaning: patients may need to endure treatment and wait for their bodies to heal.