Casual wear is a Western dress code that is relaxed, occasional, spontaneous and suited for everyday use. Casual wear became popular in the Western world following the counterculture of the 1960s. When emphasising casual wear's comfort, it may be referred to as leisurewear.
While casual is "informal" in the sense of "not formal", informal attire traditionally refers to a Western dress code associated with suits - a step below semi-formal attire - thus being more formal than casual attire.