HI,
Go to the Safari Menu Bar, click Safari/Preferences. Make note of all the preferences under each tab. Quit Safari. Now go to ~/Library/Preferences and move this file
com.apple.safari.plist to the Desktop. Relaunch Safari.
If you can launch Safari and reset your Preferences then move that .plist file to the Trash.
If that doesn't help, Go here for trouble shooting 3rd party plugins or input managers which might be causing the problem.
Safari: Add-ons may cause Safari to unexpectedly quit or have performance issues
Web pages now include a small icon or 'favicon' which is visible in the address bar and next to bookmarks. These icons take up disk space and slow Safari down. It is possible to erase the icons from your computer and start fresh. *To delete Safari's icon cache using the Finder, open your user folder, navigate to ~/Library/Safari/ and move this file "webpageIcons.db to the Trash.* Relaunch Safari.
Might want to empty the Safari cache too. From the Safari Menu Bar, click Safari / Empty Cache.
Carolyn 🙂