Zygotic 

Acting both psychotic and immature at the same time.

That man-child is acting zygotic

Zygotic by deepinthemoney April 25, 2025

zygotic episode 

Polite but meaningful phrase to convey that the couple are trying to conceive a child, particularly if the parents are crazy in love. A riff on "psychotic episode"

Claire and Jim are having a 'zygotic episode'

zygotic episode by giftedone May 27, 2009

Zygotic episode 

“Polite but meaningful phrase” to convey that a couple were trying to conceive a child. Coined by a contributor to Barbara Wallraff's Word Fugitives column, The Atlantic Monthly, March 2008.

Henry and Elizabeth had a zygotic episode.

Zygotic episode by Zvezdochka September 3, 2011

Non-zygotic Twins 

Relationship between two people who share no common genetic material but who share eerily similar mannerisms, speech patterns, behaviors and/or appearance

"Are you two brother and sister??"
"What? No! We are not at all related "
"Well you're definitely non-zygotic twins then , because you act so much alike it is freaky"

Non-zygotic Twins by Magster Dragster November 17, 2016

zygotinous 

An insult pertaining to an individual who has failed to develop further than a zygote, coined by grump of Game Grumps Arin Hanson (The video game boy, the one who wins)

“That Harry, pretty zygotinous isn’t he?”
"AHHH FUCKIN' ZYGOTINOUS PIECE OF SHIT"

zygotinous by BrasilianInglish June 18, 2019