栄枯盛衰[eikoseisui] ups and downs of life
減衰[gensui] attenuation
減衰器[gensuiki] attenuator
古び衰える[furubiotoroeru] to waste away
弱り衰える[yowariotoroeru] to languish

神経衰弱[shinkeisuijaku] neurasthenia
衰える[otoroeru] to become weak
衰え果てる[otoroehateru] to be utterly spent or crushed
衰運[suiun] declining fortunes
衰躯[suiku] emaciated body

巨躯[kyoku] big frame
衰躯[suiku] emaciated body
全躯[zenku] the whole body
体躯[taiku] the body
矮躯[waiku] small stature

病躯[byouku] sick body
躯幹[kukan] body
長躯[chouku] tall figure
痩躯[souku] lean (figure)