A "leave in conditioner for dry frizzy hair" is a noun phrase that describes a hair care product designed to detangle, moisturize, and defrizz dry, unruly hair. An example of such a product is "Leave-In Conditioner for Dry Hair by SheaMoisture".
Leave-in conditioners are important for dry frizzy hair because they provide deep hydration, reduce breakage, and add shine. The historical development of leave-in conditioners can be traced back to the early 20th century, when hairdressers began experimenting with applying hair oils and creams without rinsing them out.