minor tranquillizer vs minor tranquilliser

minor tranquillizer and minor tranquilliser both are nouns.

Word	Noun	Adjective	Verb	Adverb
minor tranquillizer	Yes	No	No	No
minor tranquilliser	Yes	No	No	No

As nouns, minor tranquillizer and minor tranquilliser are synonyms defined as:

minor tranquillizer and minor tranquilliser: a tranquilizer used to relieve anxiety and reduce tension and irritability

Other synonyms of minor tranquillizer include antianxiety drug, anxiolytic, anxiolytic drug, minor tranquilizer.

minor tranquillizer (noun)	minor tranquilliser (noun)
a tranquilizer used to relieve anxiety and reduce tension and irritability	a tranquilizer used to relieve anxiety and reduce tension and irritability