introvert
noun
in·tro·vert
| \ ˈin-trə-ˌvərt
\
\
Definition of introvert
(Entry 1 of 2)
1
: one whose personality is characterized by introversion
especially
: a reserved or shy person who enjoys spending time alone
His research further shows that about 70% of top executives are introverts. — Linda Grant
— compare extrovert
2
: something (such as the retractile proboscis of some worms) that is or can be drawn in especially by invagination