Maybe bitter king secretes billions, having more upstairs? (5)
I believe the answer is:
abler
'secretes billions having more upstairs?' is the definition.
I can't tell whether this definition defines the answer.
'maybe bitter king' is the wordplay.
'maybe bitter' becomes 'able' (I can't justify this - if you can you should believe this answer much more).
'king' becomes 'R' (abbreviation for rex, king in Latin).
'able'+'r'='ABLER'
Can you help me to learn more?
(Other definitions for abler that I've seen before include "More proficient" , "More competent, perhaps like seaman" , "More skilled" , "More skilful" , "More capable" .)