If "under-" comes in front of the word, does it mean it's "short of something"?

What does "be used to" mean?

To be "used to" in this context means that one is familiar with something, or something appears normal to someone. Ex: Many people don't like cold weather but I'm used to it. Ex: She's not used to driving yet, she needs more practice.

What does "shrugged" mean?

"Shrugged" is an action. It's when you lift your shoulders momentarily and lower them to express doubt, indifference, or uncertainty toward something. Ex: He shrugged his shoulders when the teacher asked him a question. Ex: I didn't know what to say, so I just shrugged.

Are "head pilot" and "senior pilot" the same?

When "head" is added before a title or position, we can assume that it means "person in charge." For example, a head teacher would be the teacher in charge and thus have more seniority over other teachers. "Senior pilot" means the same thing, or "pilot in charge." Thus we can see "head pilot" (unofficial term) and "senior pilot" (official term) to be two ways to describe the same position, pilot in charge. Ex: He's the senior pilot for this flight. Ex: I'm the head scientist of this lab, so I have more managerial duties than the other scientists here.

If "under-" comes in front of the word, does it mean it's "short of something"?

The prefix "under" can mean "not enough", but it can also mean "below" "beneath" "less" and "lower", depending on the word and context. Some examples of more words with "under" as a prefix are: underground (below ground), undergraduate (lower than graduate), and understated (less).

What does "you people" mean here? Is there any difference between saying "you people" and "people"?

"You people" is just another way of saying "you guys" or "everybody," but it's a little more casual in feeling. Be careful when you use it, because it's often used in negative situations when you want to sound a bit rude. Ex: I have something to tell you people. Ex: You people are crazy.