Gliding dance (3-4)
I believe the answer is:
two-step
'gliding dance' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for two-step that I've seen before include "Sot wept doing ballroom dance" , "Dance (not pas de deux!)" , "Old time dance" , "Gliding dance" , "Ballroom dance in march or polka time" .)