衰微 is read as すいび (suibi) and means decline.
すいび
suibi
おとろえる
to become weak
すいたい
decline
おとろえ
weakening
すいじゃく
weakness
すいたいいっと
(falling into a) continuous decline
すいたいき
phase of decline
すいせい
this decadent world
すいし
becoming emaciated and die
すいうん
declining fortunes
downward tendency
おとろえはてる
to be utterly spent or crushed
すいじゃくし
death from prostration