There are multiple origins and meanings for the name Hagar:
1. Hebrew name (הגר) meaning - "migrate, immigrate, emigrate; fugitive".
Hagar according to the Abrahamic faiths, was the second wife of Abraham, and the mother of his first son, Ishmael, Her story is recorded in the Book of Genesis, mentioned in Hadith, and alluded to in the Qur'an. Hagar's son, Ishmael, is the patriarch of the Ishmaelites.
2. Form of the Arabic name Hijra meaning - "migration of the prophet Muhammad".