tranquillizer vs tranquilizer

tranquillizer and tranquilizer both are nouns.

Word	Noun	Adjective	Verb	Adverb
tranquillizer	Yes	No	No	No
tranquilizer	Yes	No	No	No

As nouns, tranquillizer and tranquilizer are synonyms defined as:

tranquillizer and tranquilizer: a drug used to reduce stress or tension without reducing mental clarity

Other synonyms of tranquillizer include antianxiety agent, ataractic, ataractic agent, ataractic drug, tranquilliser.

tranquillizer (noun)	tranquilizer (noun)
a drug used to reduce stress or tension without reducing mental clarity	a drug used to reduce stress or tension without reducing mental clarity