One senior blocking obstinate person's bad government (7)
I believe the answer is:
misrule
'bad government' is the definition.
(I've seen this before)
'one senior blocking obstinate person's' is the wordplay.
'one' becomes 'i' (Roman numeral).
'senior' becomes 'sr.' (similar in meaning).
'blocking' indicates putting letters inside (to block can mean to plug a gap in something).
'obstinate person' becomes 'mule' (I've seen this before).
'i'+'sr'='isr'
'isr' put into 'mule' is 'MISRULE'.
(Other definitions for misrule that I've seen before include "Disorder (lord of)" , "Unfair government; disorder" , "Bad government" .)