Elegant, like a frock (6)
I believe the answer is:
dressy
'elegant' is the definition.
(I've seen this before)
'like a frock' is the wordplay.
I cannot quite understand how this works, but
'like' could be 'y' (similar in meaning) and 'y' is found within the answer.
'frock' could be 'dress' (synonyms) and 'dress' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for dressy that I've seen before include "swish" , "(Of clothes) smart, formal" , "'Stylish, smart (6)'" , "Elaborate" , "Liking to wear fancy or formal clothes" .)