Unsui

 The term unsui, which literally translates as "cloud, water" comes from a Chinese poem which reads, "To drift like clouds and flow like water." 

since followers of Zen attempt to move freely through life, without the constraints and limitations of attachment, like free-floating clouds or flowing water 

According to the Oxford Dictionary of Buddhism the term unsui is also used for

Ch'an or zen monks who, having achieved enlightenment (satori)  

after an initial period of training under their first master 

take to the road in search of other masters.  

This is done in order to either test their awakening against them or deepen it with them.  

The term refers to their lack of a fixed abode during this period."