This is the 11858th most frequent Polish word.
kretynie
"Idiot" or "moron" (an insulting term).
In this sentence, 'kretynie' is used vocatively to address someone directly, often in an informal, derogatory manner.
Nie bądź taki, kretynie!
Don't be like that, moron!
Here, 'kretynie' is again vocative, used in a context of expressing frustration or annoyance when addressing someone.
On powiedział, że to twój plan, kretynie.
He said this was your plan, moron.
'Kretynie' is used vocatively in an exclamation expressing disapproval or criticism directly toward someone.