We have many words for money not earned. Among other words, Ransom, Extortion, Dowry, Alimony & Maintenance based on the context. However, the concept of forcing by threat of life or litigation; any party to part with their life savings or their projected life savings is the same irrespective of the word used. The underlying element is illegal force, for no man may be forced to live for another.
Simply speaking, the first three words, Ransom, Extortion and Dowry are explicitly classified as illegal by law. But illegal force is not just something that happens outside the law. Sometimes the law can also be illegal. As is the classic and contemporary case of IPC 498A, DV Act and many Maintenance Laws. By forcing any man to part with money to any woman on just the basis of the fact that he is the husband or seemingly the husband or simply accused to be the husband, with the threat of state sponsored force, is itself an act of illegal force under the pretense of law and justice.
To wrap it up, Alimony is equal to Ransom & Maintenance is equal to Extortion.