Hostess to an extent in short dress (6)
I believe the answer is:
geisha
'hostess' is the definition.
(Japanese woman hosting or entertaining men)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for geisha that I've seen before include "A Japanese woman who entertains men" , "Jap. hostess" , "Japanese paid companion" , "He's a GI (anag.)" , "Japanese girl trained to entertain men" .)