I offen wonder does Sikh and khalsa mean the same thing and can terms be ussed intermittently.

I wonder why we never think [beforehand] about what we say [before we say it].
If we thought before we spoke, the silence would be deafening.
IMO A Sikh is one who follows only Sikh Gurus. A Khalsa can be anyone who is accepted by Guru whether he follows Gurus faith or not.