About to get English monarch humming (7)
I believe the answer is:
reeking
'humming' is the definition.
(to hum is to smell or reek)
'about to get english monarch' is the wordplay.
'about to get' becomes 're' (I've seen this in other clues).
'english' becomes 'E' (abbreviation).
'monarch' becomes 'king' (male monarch).
're'+'e'+'king'='REEKING'
(Other definitions for reeking that I've seen before include "Stinking" , "Having a foul smell" , "Giving off a strong smell" , "Foul smelling" , "Emitting smoke" .)