A useless piece of oratory or a yarn (6)
I believe the answer is:
angora
'a yarn' is the definition.
(angora is a type of yarn)
'a useless piece of oratory' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is found within the answer.
'piece' could be 'r' (abbreviation for Rook) and 'r' is found within the answer.
'of' could be 'o' and 'o' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'or' acts as a link.
Can you help me to learn more?
(Other definitions for angora that I've seen before include "Soft fluffy wool" , "Breed of rabbit or cat, the former name for the Turkish capital" , "Fine wool from certain goats" , "Breed of goat, cat or rabbit" , "Soft yarn from goat" .)