This is the 676th most frequent Russian word.
уголовного
"Criminal" (relating to crime or the criminal justice system).
This context demonstrates the word 'уголовного' used as an adjective modifying 'преследования', referring to prosecution in the legal and criminal context.
Он боится уголовного преследования.
He is afraid of criminal prosecution.
Here, 'уголовного' describes 'дела', indicating the nature of the case as related to crime or criminal laws.
Судья изучил все аспекты уголовного дела.
The judge examined all aspects of the criminal case.
In this sentence, 'уголовного' modifies 'кодекса', referring to the legal code that deals with crimes and their punishments.