With the greatest respect there's a sound alternative (3)
I believe the answer is:
awe
'with the greatest respect' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'there's a sound alternative' is the wordplay.
'there's' means one lot of letters go next to another.
'sound alternative' becomes 'we' (I can't justify this - if you can you should believe this answer much more).
'a' next to 'we' is 'AWE'.
Can you help me to learn more?
(Other definitions for awe that I've seen before include "A mix of fear and wonder" , "viewed with apprehension" , "Wonder, reverence" , "Profound respect" , "Wondrous fear" .)