Splendid introduction to radio — live (4)
I believe the answer is:
rare
'splendid' is the definition.
Both the answer and definition are adjectives. Perhaps there's a link between them I don't understand?
'introduction to radio live' is the wordplay.
'introduction to' says to take the initial letters.
'live' becomes 'are' ('they live' means 'they are').
The initial letter of 'radio' is 'r'.
'r'+'are'='RARE'
Can you help me to learn more?
(Other definitions for rare that I've seen before include "Scarce or uncommon" , "Excellent; uncommon" , "Seldom - unusual" , "little done?" , "Exceptionable" .)