Staunch is an Adjective
It means firmly in favor of, truly committed, loyal, believe strongly in something
Note : It is sometimes used as a verb which means to arrest the flow of a liquid (usually blood)
Noun : Staunchness
Adverb : Staunchly
1. I am a staunch supporter of the ban that has been imposed on smoking in public places.
2. Mahatma Gandhi was a staunch defender of non violence.
3. My friend is such a staunch atheist that no arguments are able to convince him of the existence of god.