Workforce organisers in corporation making monotonous sound (5)
I believe the answer is:
thrum
'monotonous sound' is the definition.
'workforce organisers in corporation' is the wordplay.
'workforce organisers' becomes 'hr' (abbreviation for Human Resources).
'in' means one lot of letters goes inside another.
'corporation' becomes 'tum' (I've seen this before).
'hr' placed within 'tum' is 'THRUM'.
'making' acts as a link.
(Other definitions for thrum that I've seen before include "something fibrous" , "Make a rhythmic hum" , "Monotonously repeat" , "Continuous rhythmic humming sound" , "Drone; tap idly" .)