Ray's joyful expression? (4)
I believe the answer is:
beam
This clue might be a double definition.
'ray's' is the first definition.
(synonyms)
'joyful expression?' is the second definition.
The answer and definition can be both human attributes as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for beam that I've seen before include "Rafter - smile - width" , "Radiant smile; timber support" , "giving a broad smile" , "Smile, transmit (radio signal)" , "Column of light" .)