User-agent: SemrushBot
Disallow: /index.php/catalogsearch
Disallow: /catalogsearch

User-agent: AhrefsBot 
Disallow: /index.php/catalogsearch
Disallow: /catalogsearch

User-agent: Googlebot
Disallow: /index.php/catalogsearch
Disallow: /catalogsearch

User-agent: Bingbot
Disallow: /index.php/catalogsearch
Disallow: /catalogsearch