NU’EST W (뉴이스트 W) is a four-member subunit of the boy group NU’EST. The unit was formed due to Minhyun’s temporary hiatus from the group after making to the finals on Produce 101 Season 2 to become a member of Wanna One. They released their first single ‘If You” on July 26, 2017. The ‘W’ in their name stands for “wait”.

Source: kpop wiki