Lord may be heard yielding nothing (6)
I believe the answer is:
barren
'nothing' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'lord may be heard' is the wordplay.
'lord' becomes 'baron' (baron is a kind of lord).
'may be heard' shows a homophone (sound like).
'baron' is a homophone of 'BARREN'.
'yielding' acts as a link.
Can you help me to learn more?
(Other definitions for barren that I've seen before include "'Desolate, fallow (6)'" , "Infertile, unproductive" , "Unable to bear young" , "Infertile, unable to grow things" , "Not fertile or productive" .)