What does Messiah mean?

The Angels said, "O Mary, God gives you good news of a Word from Him. His name is the Messiah, Jesus, son of Mary, well-esteemed in this world and the next, and one of the nearest.

He will speak to the people from the crib, and in adulthood, and will be one of the righteous." Quran 3:45-46

What does it mean that Jesus (Isa) is the Messiah?

In the Hebrew Bible, a  messiah (or mashiach) is a king or High Priest traditionally anointed with holy anointing oil.

The translation of the Hebrew word Mašíaḥ as Χριστός (Khristós) in the Greek Septuagint became the accepted Christian designation and title of Jesus of Nazareth

Why do the nations conspire and the peoples plot in vain?  The kings of the earth rise up and the rulers band together against the Lord and against his anointed, saying, “Let us break their chains and throw off their shackles.” The One enthroned in heaven laughs; the Lord scoffs at them. He rebukes them in his anger and terrifies them in his wrath, saying, “I have installed my king on Zion, my holy mountain.” Psalm 2:2 (Zabur)

On the eighth day, when it was time to circumcise the child, he was named Jesus, the name the angel had given him before he was conceived. Luke 2:21

The woman said, “I know that Messiah” (called Christ) “is coming. When he comes, he will explain everything to us.”  Then Jesus declared, “I, the one speaking to you—I am he.” John 4:25-26

 She will give birth to a son, and you are to give him the name Jesus, because he will save his people from their sins.” Matthew 1:21

Jesus (Isa) is the anointed one and He is the only one who can forgive and save people from their sins J