gut
Your stomach and intestines where food is digested.
Gut is your digestive system, especially your stomach and intestines, where food gets broken down after you eat. But the word also describes instinctive feelings that seem to come from deep inside you.
When you have a gut feeling about something, you sense it's right or wrong without being able to explain exactly why. Maybe you meet someone new and your gut tells you they're trustworthy, or you're about to make a choice and something in your gut says “wait.” These feelings aren't random: your brain picks up on tiny details you don't consciously notice, and that information surfaces as a gut reaction.
People also use gut to mean courage or determination. Someone with guts faces scary situations despite being afraid. A student shows guts by admitting a mistake in front of the class. When you do something difficult that requires bravery, you might gut it out and push through anyway.
The word appears in many expressions: a gut check means honestly evaluating a situation, a gut-wrenching experience is deeply upsetting, and a gut punch (literally a punch to the stomach) describes any sudden, devastating blow. People describe their gut reaction to something as their immediate, instinctive response before they've had time to think it through carefully.