Make pompous speech no-one admires? (5)
I believe the answer is:
orate
'make pompous speech' is the definition.
(to orate is to give a formal speech)
'no-one admires?' is the wordplay.
'no' becomes 'O' (resembles 0 - 'no' can mean 'zero').
'one admires?' becomes 'rate' (I can't explain this - if you can you should believe this answer much more).
'o'+'rate'='ORATE'
(Other definitions for orate that I've seen before include "Hold forth" , "Pontificate" , "make speeches" , "Talk pompously" , "Give a formal address" .)