noun
Refers to a person who makes or alters clothing professionally. Covers both men's tailoring and women's dressmaking.
彼は腕のいい仕立て屋だ。
He is a skilled tailor.
このスーツは仕立て屋で直してもらった。
I had this suit altered at the tailor's.
洋服屋 is a broader term for a clothing store, while 仕立て屋 specifically refers to a tailor or dressmaker who makes or alters garments.
Compound of 仕立て (したて, 'tailoring, making') + 屋 (や, 'shop, person'). The spelling 仕立て comes from the verb 仕立てる (したてる, 'to tailor, to make').