designer vs couturier

designer and couturier both are nouns.

Word	Noun	Adjective	Verb	Adverb
designer	Yes	No	No	No
couturier	Yes	No	No	No

As nouns, designer and couturier are synonyms defined as:

Other synonyms of designer include clothes designer, fashion designer.

designer (noun)	couturier (noun)
someone who creates plans to be used in making something (such as buildings)	someone who designs clothing
someone who designs clothing
a person who specializes in interior design
a person who devises plots or intrigues
someone who specializes in graphic design