I. ˈshət-ˌin noun
Date: 1891
1. : a person who is confined to home, a room, or bed because of illness or incapacity
2. : a narrow gorge-shaped part of an otherwise wide valley
3. : available oil or gas which is not being produced from an existing well
II. ˈshət-ˈin adjective
Date: 1909
1. : confined to one's home or an institution by illness or incapacity
2.
a. : secretive , brooding
a bitter, shut-in face — Claudia Cassidy
b. : tending to avoid social contact : withdrawn
the shut-in personality type — S. K. Weinberg