Source : WordNet®

go under
     v 1: go under, "The raft sank and its occupants drowned" [syn: {sink},
           {settle}, {go down}] [ant: {float}]
     2: disappear beyond the horizon; "the sun sets early these
        days" [syn: {set}, {go down}] [ant: {rise}]
     3: be called; go by a certain name; "She goes by her maiden
        name again" [syn: {go by}]