1) Prematurely old 
Prior to the usual onset of senility, as in the milder, presenile dementia. ... (05 Mar 2000) ... 
(pre-se´nīl) pertaining to a condition resembling senility, but occurring in early or middle life.
Type: Term Pronunciation: prē-sē′nīl Definitions: 1. Before the usual onset of senility, as in the milder, presenile dementia.
pertaining to or exhibiting the characteristics of presenility; prematurely old.