Being tired
The phrase 'müde sein' is the German equivalent of 'being tired'. It is used to express a state of fatigue or exhaustion. For example, 'Ich bin müde' translates to 'I am tired'.
I could be tired because I went to bed late yesterday.
In this example, the speaker is stating a possible reason for feeling tired, which is going to bed late the previous night.
If you are tired, you should take a break.
This sentence is giving advice. The speaker is recommending the listener to take a break when they are feeling tired.
He seems to be very tired after the long flight.
In this context, the speaker is making an observation about another person's state, suggesting that the person seems tired from a long flight.