Smart king or little bird (5)
I believe the answer is:
chick
'little bird' is the definition.
'chick' can be an answer for 'bird' (I have seen 'Young bird' mean 'chick' so perhaps 'bird' could also mean 'chick'). I'm not sure about the 'little' bit.
'smart king' is the wordplay.
'smart' becomes 'chic' (both can mean stylish).
'king' becomes 'K' (chess abbreviation).
'chic'+'k'='CHICK'
'or' acts as a link.
Can you help me to learn more?
(Other definitions for chick that I've seen before include "Baby bird" , "Young bird" , "young singer" , "Young fowl" .)