Human resources entirely died during male American slavery (9)
I believe the answer is:
thralldom
'american slavery' is the definition.
'thralldom' can be an answer for 'slavery' (synonyms). I am not certain of the 'american' bit.
'human resources entirely died during male' is the wordplay.
'human resources' becomes 'HR'.
'entirely' becomes 'all' (all can mean entirely or completely).
'died' becomes 'd' (abbreviation next to the year of someone's death).
'during' indicates putting letters inside.
'male' becomes 'tom' (tom can mean a male cat).
'hr'+'all'+'d'='hralld'
'hralld' going into 'tom' is 'THRALLDOM'.
Can you help me to learn more?
(Other definitions for thralldom that I've seen before include "State of servitude" , "One's completely enslaved by it" .)