Submissive old criminal about to pass on (8)
I believe the answer is:
obedient
'submissive' is the definition.
(obedient can mean submissive to authority)
'old criminal about to pass on' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'criminal' becomes 'bent' (bent can mean corrupt or criminal).
'about' means one lot of letters goes inside another.
'to pass on' becomes 'die' (pass on can mean to die).
'bent' going around 'die' is 'bedient'.
'o'+'bedient'='OBEDIENT'
(Other definitions for obedient that I've seen before include "Ready to comply" , "Like monk" , "Ready to agree" , "Amenable" , "Submissive, biddable" .)