The term is evidently a karmadhaaraya. Compare, for instance, the
juxtapposition of ta.nhakkhaya, viraaga, nirodha and nibbaana at S I 136. In
the cpd. asesa qualifies viraaga conplete fading away (syntactically to be
construed with whatever nominal denoting the thing that is fading away)+
nirodha: annihilation which is the complete fading away of e.g. passion,
thirst ignorance or the like.