Perjury, subornation of perjury, concealment of subpoenaed documents, and witness tampering are all forms of obstruction of justice.

CNN: Sen. Allard's closed-door impeachment statement

We make perjury, subornation of perjury, obstruction of justice and witness tampering crimes because a judicial system can only succeed if its procedures expose the truth.

CNN: Transcript: House Judiciary Committee

Under this scenario, Starr would seek an indictment of Lewinsky for perjury and subornation of perjury for her alleged efforts to get co-worker Linda Tripp to lie under oath to Jones' attorneys.

CNN: Investigating the President