I. ˈsēˌnīl also ˈseˌ- sometimes -_n ə l or -(ˌ)nil adjective
Etymology: Latin senilis, from sen-, senex old, old man + -ilis -ile — more at senior
1. : of, relating to, or characteristic of old age
senile weakness
senile decay
senile wisdom
2.
a. : showing the characteristics of old age : aged
a senile porter still handling baggage
shoes that looked positively senile
b. : marked by the weakness of old age : decrepit
a senile person
a senile empire
especially : exhibiting a loss of mental faculties associated with old age : doddering
the oldest man and woman of the group are regarded as the ultimate authority, if they are not senile — E.H.Spicer
3. : approaching the end of a geological cycle of erosion
a senile topography
a senile river
II. noun
( -s )
: a senile person : dotard 1b