Definition of boink:
(v) :
(ambitransitive, informal) To have sexual intercourse (with); to bonk.
(n) :
(informal) Sexual intercourse.
(v) :
(transitive, informal) To hit or strike.
(n) :
A sound of something hitting or bouncing off a surface, similar to plunk, but with more connotations of bounciness.
(n) :
(computing, slang) A real-world social gathering of computer users.