Elizabeth Proctor feels antagonistic toward her former servant Abigail, who had an affair with her husband, calling her “something soiled.” Elizabeth, who is morally upright and a bit cold, won't sit near Abigail at church. She also hints to neighbors that Abigail is no saint without actually accusing her husband of adultery.
Elizabeth is convinced that Abigail would like her to die and wants to murder her. Elizabeth also accuses Abigail of vanity over her good looks, which is part of Elizabeth perceiving her former maid as a whore. Elizabeth also says she dismissed Abigail from service because she was a poor housekeeper. Abigail, in turn, calls Elizabeth “a bitter woman, a lying, cold, sniveling woman.”
These kinds of bitter feelings lead to bigger problems later on. Abigail does try to frame Elizabeth as a witch, which is a way to try to murder or get rid of her.