Young creatures concealed by long dresses (6)
I believe the answer is:
calves
'young creatures' is the definition.
'calves' can be an answer for 'creatures' (calf is a kind of creature). I am not certain of the 'young' bit.
'concealed by long dresses' is the wordplay.
I cannot quite understand how this works, but
'long' could be 'l' and 'l' is found in the answer.
The remaining letters 'caves' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
(Other definitions for calves that I've seen before include "Young farm animals" , "features of legs" , "Young cows" , "Backs of legs" , "Young domestic cattle" .)