Obsessionally is an adverb that describes a behavior or activity that is done in an excessive, extreme, and compulsive manner. There are several synonyms that can be used to replace or describe the word obsessionally, such as fanatically, passionately, zealously, fervently, compulsively, maniacally, obsessively, resolutely, determinedly, single-mindedly, intently, and fixatedly. Each of these synonyms has a slightly different connotation, but all of them imply a strong and persistent focus or attachment to something. Whether it is a hobby, a goal, or a person, behaving obsessionally can be both positive and negative depending on the situation.