geek

US /ɡiːk/
UK /ɡiːk/
"geek" picture
1.

a person who is extremely enthusiastic and knowledgeable about a particular subject, especially one that is obscure or difficult

:
He's a computer geek who can fix any software problem.
My brother is a total history geek; he knows everything about ancient civilizations.
2.

a person who is socially awkward or unpopular, often associated with intellectual pursuits

:
He was often called a geek in high school because he preferred books to parties.
She felt like a social geek at the party, unsure how to interact.
1.

to act like a geek; to obsess over a particular subject

:
He tends to geek out on vintage video games whenever he has free time.
I could really geek out about the new advancements in space exploration.