Calls urgently for piano wires (6)
I believe the answer is:
pleads
'calls urgently' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot see how one could define the other.
'piano wires' is the wordplay.
'piano' becomes 'p'.
'wires' becomes 'leads' (lead is a kind of wire).
'p'+'leads'='PLEADS'
'for' is the link.
Can you help me to learn more?
(Other definitions for pleads that I've seen before include "Appeals or requests earnestly" , "Begs" , "Makes appeal or entreaty" , "Implores" .)