Pass one bill in ten after amendment (5)
I believe the answer is:
enact
'pass' is the definition.
(I know this)
'one bill in ten after amendment' is the wordplay.
'one bill' becomes 'ac' (short for account).
'in' means one lot of letters goes inside another.
'ten after amendment' becomes 'ent' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ac' inserted into 'ent' is 'ENACT'.
Can you help me to learn more?
(Other definitions for enact that I've seen before include "get into law" , "Pass into law" , "Play one's part" , "Put into practice" , "Present" .)