Hello @kartik,
You can specify custom error message for your field as follows.
$messages = array(
'cat.required' => 'The category field is required.',
);
$validator = Validator::make($input, $rules, $messages);
Or you can keep a mapping for your field names like below. And you can set those into you validator. So you can see descriptive name instead of real field name.
$attributeNames = array(
'name' => 'Name',
'cat' => 'Category',
);
$validator = Validator::make ( Input::all (), $rules );
$validator->setAttributeNames($attributeNames);
Hope it helps!!
Thank You!!