The noun safeguard is a common noun, a word for any safeguard of any kind.
A proper noun is the name of a person, place, thing, or a title; for example:
- McGruff Safeguard, website of McGruff the Crime Dog and the National Crime Prevention Council
- Safeguard Street, Houston, TX; Safeguard Street, Honolulu, HI; or Safeguard Place, Irvine, CA
- Safeguard Antibacterial Soap
- "The Safeguard: A Novel of Georgia in 1864" by Diana Wilder