Underworld is crooked and determined to achieve at all costs
I believe the answer is:
hellbent
'determined to achieve at all costs' is the definition.
I can't tell whether this defines the answer.
'underworld is crooked' is the wordplay.
'underworld' becomes 'hell' ('Hell' can be a synonym of 'underworld').
'is crooked' becomes 'bent' ('bent' can be similar in meaning to 'crooked').
'hell'+'bent'='HELLBENT'
'and' is the link.
Can you help me to learn more?
(Other definitions for hellbent that I've seen before include "Rashly determined" , "Recklessly resolute" , "Dogged - persistent" , "Recklessly determined - on way to Hades?" , "Implacably set (on)" .)