Big ask for retired comic to replace steel cap in taser (4,5)
I believe the answer is:
tall order
'retired comic to replace steel cap in taser' is the definition.
I can't tell whether this defines the answer.
'big ask' is the wordplay.
'big' becomes 'tall'.
'ask' becomes 'order' (ordering is a kind of asking).
'tall'+'order'='TALL ORDER'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for tall order that I've seen before include "Difficult instruction" , "for brotherhood of high standing" , "as the building of Babel was?" , "Request to tax" , "not easily satisfied" .)