senility (n.)

• abulia
• age
• ancientness
• antiquity
• atavism
• childishness
• debility
• decline
• decrepitude
• dipsomania
• dotage
• eld
• eldership
• feebleness
• incapacity
• infirmity
• insipidity
• instability
• invalidism
• longevity
• neurosis
• oldness
• primitiveness
• primogeniture
• psychopathy
• psychosis
• ricketiness
• senescence
• seniority
• shakiness
• superannuation
• unsoundness
• unsteadiness
• vapidity
• venerableness
• wateriness