If someone perverts the course of justice, they deliberately do something that will make it difficult to discover who really committed a particular crime, for example, destroying evidence or lying to the police.
1. a person whose behavior deviates from what is acceptable especially in sexual behavior
Verb
1. corrupt morally or by intemperance or sensuality;
"debauch the young people with wine and women""Socrates was accused of corrupting young men""Do school counselors subvert young children?""corrupt the morals"
2. practice sophistry; change the meaning of or be vague about in order to mislead or deceive
3. change the inherent purpose or function of something;
"Don't abuse the system""The director of the factory misused the funds intended for the health care of his workers"