Hideous newborn's masculine when undressed (7)
I believe the answer is:
abysmal
'hideous' is the definition.
Both the answer and definition are adjectives. Maybe there's an association between them I don't understand?
'newborn's masculine when undressed' is the wordplay.
'newborn's' becomes 'abysm' (I can't justify this - if you can you should give a lot more credence to this answer).
'masculine' becomes 'male' (similar in meaning).
'when undressed' says to take the centre (remove the outside letters which 'dress' the word).
The middle of 'male' is 'al'.
'abysm'+'al'='ABYSMAL'
Can you help me to learn more?
(Other definitions for abysmal that I've seen before include "Very bad or bottomless" , "Appallingly bad" , "Deep, immeasurable" , "Really terrible" , "Dreadful" .)