1. showing extreme enthusiasm or devotion that is often unreasonable or excessive

Examples

• She was fanatical about keeping her house spotlessly clean.
• The team’s fanatical supporters traveled across the country to every game.
• His fanatical devotion to exercise meant he worked out for three hours daily.
• The cult leader had fanatical followers who obeyed his every command.
• Her fanatical attention to detail made her an excellent editor.
• The politician’s fanatical supporters refused to listen to any criticism.