imperative
crucial
definitely, absolutely, without a doubt, surely, unquestionably, of course, positively.
I have absolutely no idea what i am doing.
No, Absolutely not
Necessary is not an adverb: it is most commonly used as an adjective.
more necessary, most necessary
Unnecessary
Absolutely necessary.
absolutely
Another word for obligatory is "required" or "necessary".
AppallingAwfulBloodcurdlingDreadfulFearfulFrightfulFrieghteningGhastlyGrimGrislyGruesomeHair-raisingHideousHorrendousHorridHorrificLuridMacabreShockingTerribleTerrifying
Existent is another word for actually. Absolutely and indeed are additional synonyms for actually.
Absolutely is another word for unconditionally. Additional synonyms include completely and thoroughly.
required, obligatory
Necessary or desired
Other words for require:demandrequest
http://thesaurus.reference.com/browse/necessary use these word at this website and it will help you
no