Replace unwanted words with preferred alternatives.

<?php
declare(strict_types=1);

/**
 *
 * Features:
 * - Case-insensitive matching
 * - Easy to extend (just edit the $replacements array)
 * - Safe for any input (typed and validated)
 */
function cleanText(string $text): string
{
    $replacements = [
        'asshole' => 'mate',
        'arse'   => 'bottom',
    ];

    return str_ireplace(
        array_keys($replacements),
        array_values($replacements),
        $text
    );
}

// Example
$original = "Oi asshole, Im gonna kick your arse on COD!";
$cleaned  = cleanText($original);

echo $cleaned;

Result = Oi mate, Im gonna kick your bottom on COD!