Should such a stool be soft? (5)
I believe the answer is:
piano
'soft?' is the definition.
('piano' can be similar in meaning to 'soft')
'should such a stool' is the wordplay.
I cannot quite see how this works, but
'a' could be 'an' and 'an' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'be' acts as a link.
Can you help me to learn more?
(Other definitions for piano that I've seen before include "Direction in music (1): relatively softly" , "Musical instrument - softly, please" , "entertain with this softly" , "Stringed instrument - to be played quietly" , "Franz Liszt's instrument" .)