There are several synonyms for the phrase "be obliged." One common synonym is "be obligated," which implies a sense of responsibility or duty. Another synonym is "be beholden," which conveys a sense of indebtedness or gratitude. "Be duty-bound" is another synonym that emphasizes a commitment or obligation based on a specific duty or role. "Be required" is a synonym that conveys a sense of necessity or urgency. Finally, "be compelled" is a synonym that emphasizes a feeling of being forced or pushed to act in a certain way. Overall, these synonyms help to convey the various nuances and shades of meaning associated with the phrase "be obliged".