Obligately is a word that means something that is required or necessary. There are several synonyms that can be used in place of obligately, depending on the context of the sentence. Some of the synonyms that can be used for this word include necessarily, invariably, compulsorily, needfully, and indispensably. Each of these words can be used interchangeably with obligately to express the same meaning. For example, one could say "He is necessarily required to do his job" instead of "He is obligately required to do his job." In each case, the meaning of the sentence remains the same with a different word used to convey the same idea.