This is the 502nd most frequent Russian word.
уголовное
"Criminal" (related to crime or criminal law).
In this sentence, 'уголовное' is used as an adjective, describing the type of law, specifically related to crimes and punishments.
Уголовное право занимается изучением преступлений и наказаний.
Criminal law deals with the study of crimes and punishments.
Here, 'уголовного' is in the genitive case, specifying the nature of the offense, showing its relation to criminal law.
Его обвинили в совершении уголовного преступления.
He was accused of committing a criminal offense.
In this example, 'уголовным' is in the instrumental case, contrasting the types of law being discussed.