He is a habitual criminal.他是一个惯犯。

criminal还可用作形容词,作“犯罪的,刑事的”解,通常作定语,且不用于比较等级。例如:
Theft is a criminal act.偷盗是犯罪行为。
A criminal lawyer is a specialist in criminal law.刑事律师是刑法专家。

［同义词］   convict, lawbreaker
［词源］＜古法语criminel(罪行的)