Remarkable to keep business department in servitude (6)
I believe the answer is:
thrall
'servitude' is the definition.
(I've seen this before)
'remarkable to keep business department' is the wordplay.
'remarkable' becomes 'tall' (I've seen this before).
'to keep' indicates putting letters inside.
'business department' becomes 'hr' (I can't explain this - if you can you should believe this answer much more).
'tall' enclosing 'hr' is 'THRALL'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for thrall that I've seen before include "In . . . . . . means in bondage" , "The state of being under the control of another person" , "subjection" , "captivity" , "Slave(ry)" .)