Hot green dresses are imitations (4)
I believe the answer is:
echo
'hot green dresses are imitations' is the definition.
I can't tell whether this defines the answer.
'hot green dresses' is the wordplay.
'hot' becomes 'h' (abbreviation eg on taps).
'green' becomes 'eco' (eco-friendly).
'dresses' indicates putting letters inside (some letters are contained by or dressed in others).
'h' going into 'eco' is 'ECHO'.
Can you help me to learn more?
(Other definitions for echo that I've seen before include "E; reverberation" , "Repetition of sound" , "Say again or imitate" , "Nymph whose love Narcissus spurned" , "Nymph (only able to repeat the last words of others)" .)