How can I startup my intel mac with wifi disabled?

How can I startup my intel mac with wifi disabled?

By turning wi-fi off before you shut down the Mac, either in the toolbar or in System Preferences > Network. The Mac should restart with wi-fi off.

If you have wi-fi set at On when it was shut down, and need to make sure your Mac is not connected to a network or the internet after startup, turn off your network modem or router first then turn off wi-fi on the Mac before restarting your router or modem. This will prevent an internet connection.

What has prompted your question? Are you using ethernet to connect to a network, or do you want the Mac as a standalone computer?